Hi David:
Thanks for answering. I've got the sample log attached. The key lines that I've identified are:
[line 484] 'ApplyCrdDocToDbDoc of form rmApply', 1, 7, "WCREDT00003453", 9/27/2021, 9/27/2021, "", 1, "INV00276572", 0.00000, 53.00000, 0.00000, 0.00000, 0.00000, 0, table 'RM_Customer_MSTR', table 'RM_Module_SETP', 0
[line 594] 'Apply of form rmApply', 1, 7, "WCREDT00003453", 1, "INV00276572", 0.00000, 53.00000, 0.00000, 0.00000, 0.00000, -CAD, -CAD, 0.00000, 0.00000, 0.00000, 0.00000, 0.00000, 0.00000, 1-, 4-, 2-, of form rmOpen-, table 'MCRevalDistTEMP', table 'MC_RM_Revaluation'
[line 739] 'CommitApply of form rmApply', 1, 7, "WCREDT00003453", "I11013206", 9/27/2021, -CAD, 1, "INV00276572", "I11013206", 6/24/2020, "30062020LV", "Sales Entry", "SLSTE00018056", 4, 1, -CAD, 0, 0.00000, 0.00000, 0.00000, 0.00000, 0.00000, 0.00000, 0.00000, 0, 0, 0, 0, 0, 4-, 2-, of form rmOpen-, table 'MCRevalDistTEMP', table 'MC_RM_Revaluation', table 'RM_Customer_MSTR', table 'RM_Customer_MSTR_SUM', table 'MC_RM_Apply_Dist_TEMP', table 'RM_Distribution_WORK', 0
By line 484 the system has the list of documents that it is writing off. That's the key that I need: what documents is it trying to apply to?
In the intervening time I've been thinking about this. I probably would have to do this in two triggers: one to grab the data before its posted, and the other after it's posted to actually do what it is that I want - because if the process doesn't go through, or stops, I can't update what I need to update. So that's a piece of what I need. But I'm still stumped on where to actually find it.
The specific window that I'm running from (in case it matters) is Dynamics GP --> Tools --> Routines --> Sales --> Write Off Documents:

[View:/cfs-file/__key/communityserver-discussions-components-files/32/WTOF-routine.txt
Thanks for your help! (Or if anyone else cares to join in?)
-J