After some testing, it looks like it was not sorting because there was a find in the On Layout Enter Script that did not need to be there if I used the proper GTRR command. Does relationship based find/sort speed up performance?
Yes, a Find will produce an unsorted found set where GTRR will reproduce the sort order specified at the relationship level.
I once had a long on line argument on this subject with another developer back before we had such forums (it was an Old Listserv hosted by FileMaker Inc.).
Careful "benchmark" tests may show differences not otherwise detectable, but GTRR "finds" can often appear to be much faster than scripted finds that enter find mode, specify criteria and then perform the find. But much of that "difference" is due to the fact that GTRR requires indexed Match fields in the "target" table, where scripted finds often specify criteria in unstored or unindexed fields which will then produce a slower response. But those types of "finds" are not even possible with GTRR so it's a bit of an "apple vs. orange" comparison.
As far as I can tell, if the Find specifies criteria only in indexed fields, there is little, if any, noticeable difference in response times.