Clarification on Using ref.c in sunab Function for Reference Cohorts

[NancyYFang]

First and foremost, I want to thank you for developing this amazing package. It has been incredibly useful for my research.
I am currently using the sunab function from the fixest package and I have encountered an issue regarding the specification of reference cohorts. I would like to use both the never treated cohorts and the always treated cohorts as references in my analysis. However, I have noticed that when I try to specify additional reference cohorts using ref.c, the estimation results do not change from the default option.
Here are my specific questions:
Capability of sunab with Multiple References: Can the sunab function take both the never treated cohorts and the always treated cohorts as reference points simultaneously?
Adding More References with ref.c: How exactly can I add more reference cohorts using the ref.c argument? I have attempted to use ref.c = c(1, 10000) to include an early treated cohort (1) and a never treated cohort (10000), but the results remain unchanged from the default settings.