I did some research. The only past issue that I can find that sounds similar is:

Resolved in QIP6.7A (001122) When Update Archive was run on invoices with Inventory Control items, tax was recalculated incorrectly in some cases. This has been corrected.

Needless to say, since the problem does not exist in Adagio Invoices, I would suggest moving up the date in which they start to go 'live' with Adagio - at least with Invoices. There should be no issues using Invoices with their other ACCPAC Plus modules.

The only other suggestion I can offer is for them to NOT edit the archive batches, but to move them to the open area, do their modifications, then move them back to the archive area. This way, all they have to do when they are ready to invoice, is to restore the archived invoice(s) - no editing will be required.

This is all we can offer - since the current releases no longer have the problem, and it seems pointless to upgrade their version of QIP when they already have Adagio Invoices installed and running.

Regards