"Agile" approach of entering MMF revenue

[jodal]

A easier way to enter revenue information:

1. Enter cost periods (these are usually only a few for each MMF, so not really a problem)
2. For each MMF, enter a starting revenue value and then select one of the following with the associated parameters:
   • Flat (no parameters)
   • Linear (slope: how much is the anticipated increase/decrease in revenue per period). Of course flat is a special case of this but we thought that it was useful to have them separately.
   • Exponential growth (exponent)