diff --git a/OFM.Infrastructure.WebAPI/Extensions/TimeExtensions.cs b/OFM.Infrastructure.WebAPI/Extensions/TimeExtensions.cs
index b155200..7024d1b 100644
--- a/OFM.Infrastructure.WebAPI/Extensions/TimeExtensions.cs
+++ b/OFM.Infrastructure.WebAPI/Extensions/TimeExtensions.cs
@@ -200,6 +200,20 @@ public static DateTime GetLastBusinessDayOfPaymentMonth(this DateTime PaymentDat
 
         return lastDayOfPaymentMonth;
     }
+
+    public static DateTime GetFirstDayOfFollowingMonth(this DateTime PaymentDate, List<DateTime> holidays)
+    {
+        DateTime firstDayOfNextMonth = new DateTime(PaymentDate.Year, PaymentDate.Month, 1).AddMonths(1);
+        // Iterate backward to find the last business day of that payment month.
+        while (firstDayOfNextMonth.DayOfWeek == DayOfWeek.Saturday ||
+                firstDayOfNextMonth.DayOfWeek == DayOfWeek.Sunday ||
+                holidays.Exists(excludedDate => excludedDate.Date.Equals(firstDayOfNextMonth.Date)))
+        {
+            firstDayOfNextMonth = firstDayOfNextMonth.AddDays(1);
+        }
+        return firstDayOfNextMonth;
+    }
+
     public static DateTime GetFirstDayOfFollowingNextMonth(this DateTime PaymentDate, List<DateTime> holidays)
     {
         DateTime firstDayOfNextMonth = new DateTime(PaymentDate.Year, PaymentDate.Month, 1).AddMonths(2);
diff --git a/OFM.Infrastructure.WebAPI/Services/Processes/Payments/P520GenerateAllowancePaymentProvider.cs b/OFM.Infrastructure.WebAPI/Services/Processes/Payments/P520GenerateAllowancePaymentProvider.cs
index bfc3032..32bc4d5 100644
--- a/OFM.Infrastructure.WebAPI/Services/Processes/Payments/P520GenerateAllowancePaymentProvider.cs
+++ b/OFM.Infrastructure.WebAPI/Services/Processes/Payments/P520GenerateAllowancePaymentProvider.cs
@@ -488,15 +488,23 @@ private async Task<JsonObject> CreateSinglePayment(SupplementaryApplication appr
             DateTime invoiceDate = (paymentDate == approvedSA.ofm_start_date!.Value) ? paymentDate.GetLastBusinessDayOfThePreviousMonth(holidaysList) : paymentDate.GetCFSInvoiceDate(holidaysList, _BCCASApi.PayableInDays);
             DateTime invoiceReceivedDate = invoiceDate.AddBusinessDays(_BCCASApi.PayableInDays, holidaysList);
             DateTime effectiveDate = invoiceDate;
-            //this applies if supplementary application is submitted within 45 days.
-            if ((CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, firstAnniversaryDate) || CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, secondAnniversaryDate) || CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, fundingEndDate.Value)))
+            //this applies if supplementary application is submitted within last 45 days to last 30 days.
+
+            if ((CheckSubmissionIsWithinLastMonth(approvedSA.ofm_submittedon.Value, firstAnniversaryDate) || CheckSubmissionIsWithinLastMonth(approvedSA.ofm_submittedon.Value, secondAnniversaryDate) || CheckSubmissionIsWithinLastMonth(approvedSA.ofm_submittedon.Value, fundingEndDate.Value)))
             {
-                 invoiceReceivedDate = paymentDate.GetFirstDayOfFollowingNextMonth(holidaysList);
-                 invoiceDate = invoiceReceivedDate.GetCFSInvoiceDate(holidaysList, _BCCASApi.PayableInDays);
-                 effectiveDate = invoiceDate;
+                invoiceReceivedDate = paymentDate.GetFirstDayOfFollowingNextMonth(holidaysList);
+                invoiceDate = invoiceReceivedDate.GetCFSInvoiceDate(holidaysList, _BCCASApi.PayableInDays);
+                effectiveDate = invoiceDate;
+            }
+            else if ((CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, firstAnniversaryDate) || CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, secondAnniversaryDate) || CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, fundingEndDate.Value)))
+            {
+                invoiceReceivedDate = paymentDate.GetFirstDayOfFollowingMonth(holidaysList);
+                invoiceDate = invoiceReceivedDate.GetCFSInvoiceDate(holidaysList, _BCCASApi.PayableInDays);
+                effectiveDate = invoiceDate;
             }
 
-            if (approvedSA.ofm_retroactive_date is not null && !(CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, firstAnniversaryDate) || CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, secondAnniversaryDate) || CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, fundingEndDate.Value)))
+
+                if (approvedSA.ofm_retroactive_date is not null && !(CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, firstAnniversaryDate) || CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, secondAnniversaryDate) || CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, fundingEndDate.Value)))
             {
                 // Date calculation logic is different for mid-year supp application. Overriding regular date logic above
                 // Invoice received date is always the last business date of previous month except for first payment of the First funding year, it is 5 business day after the last business day of the last month.
@@ -560,14 +568,21 @@ private async Task<JsonObject> CreatePaymentsInBatch(Application baseApplication
                 DateTime invoiceDate = (paymentDate == startDate) ? startDate.GetLastBusinessDayOfThePreviousMonth(holidaysList) : paymentDate.GetCFSInvoiceDate(holidaysList, _BCCASApi.PayableInDays);
                 DateTime invoiceReceivedDate = invoiceDate.AddBusinessDays(_BCCASApi.PayableInDays, holidaysList);
                 DateTime effectiveDate = invoiceDate;
+
                 //this applies if supplementary application is submitted within 45 days.
-                if ((CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, firstAnniversaryDate) || CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, secondAnniversaryDate) || CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, fundingEndDate.Value)))
+                 if ((CheckSubmissionIsWithinLastMonth(approvedSA.ofm_submittedon.Value, firstAnniversaryDate) || CheckSubmissionIsWithinLastMonth(approvedSA.ofm_submittedon.Value, secondAnniversaryDate) || CheckSubmissionIsWithinLastMonth(approvedSA.ofm_submittedon.Value, fundingEndDate.Value)))
                 {
                     invoiceReceivedDate = paymentDate.GetFirstDayOfFollowingNextMonth(holidaysList);
                     invoiceDate = invoiceReceivedDate.GetCFSInvoiceDate(holidaysList, _BCCASApi.PayableInDays);
                     effectiveDate = invoiceDate;
+                }else if ((CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, firstAnniversaryDate) || CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, secondAnniversaryDate) || CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, fundingEndDate.Value)))
+                {
+                    invoiceReceivedDate = paymentDate.GetFirstDayOfFollowingMonth(holidaysList);
+                    invoiceDate = invoiceReceivedDate.GetCFSInvoiceDate(holidaysList, _BCCASApi.PayableInDays);
+                    effectiveDate = invoiceDate;
                 }
 
+
                 if (approvedSA.ofm_retroactive_date is not null && !(CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, firstAnniversaryDate) || CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, secondAnniversaryDate) || CheckSubmissionIsWithinLast45days(approvedSA.ofm_submittedon.Value, fundingEndDate.Value)))
                 {
                     // Date calculation logic is different for mid-year supp application. Overriding regular date logic above
@@ -628,9 +643,17 @@ private async Task<int> GetNextInvoiceLineNumber()
 
         private static bool CheckSubmissionIsWithinLast45days(DateTime submittedDate, DateTime anniversayDate)
         {
-            DateTime cutoffDate = anniversayDate.AddDays(-45);
+            DateTime temp = anniversayDate.AddMonths(-1);
+            DateTime cutoffDate = new DateTime(temp.Year, temp.Month, 15, 0, 0, 0).ToUTC();
 
             return submittedDate >= cutoffDate;
         }
+
+        private static bool CheckSubmissionIsWithinLastMonth(DateTime submittedDate, DateTime anniversayDate)
+        {
+           DateTime temp = submittedDate.ToUniversalTime();
+  
+            return temp.Year == anniversayDate.Year && temp.Month == anniversayDate.Month;
+        }
     }
 }
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