date field to use for dynamic AR aging

We have been asked by our users to create two reports that are based on AR aging. Both of them need to have dynamic ending dates--they need to be able to run and calculate based on today's date (or yesterday's). PerPost won't work because we will have reports run with an end date of 5/15 that goes back 30 days. This crosses two PerPosts. We need a date field for our criteria. In looking at ARDoc, we do not find one date field that consistently matches the PerPost field. We've looked at:






The DocDate or Crtd_DateTime are the obvious choices but when we compare that year/month to PerPost, in ARDoc or ARTran, we find exceptions-thousands of them. We believe that someone has to have run into this issue before. Thoughts? Solutions? Any help would be greatly appreciated!