Sry for answering so late but if you are stil dealing with speed of your app try to insert this code just before opening the tables.

lcWhereToSave="C:\app\logs\coverage.log"
SET EVENTTRACKING ON
SET COVERAGE TO lcWhereToSave

and then you'll be able to open log an read where your app has a narrow neck.

Moreover there is a lot of indexing during the code, think if you can prepare it before the bussines logic. Also lots of cycles, so try to use SQL queries insted of while cycles.

And if you must use go top / bottom thing about locate for .t. it is an optimizable command. So use it and in the case of bottom use descending indexes.

But the most valuable will be to think about to do all aggregation during one cycle.

Good luck.
R.Sehnal