We have had a few reports of something similar to this; however it is very rare and in each case the problem could not be duplicated easily. It often has to do with the deleting and re-entering of an item on an invoice. If you have a list of specific steps that can create the error from a brand new invoice batch, please post it here.

If the difference is related to a tax amount, you can edit a specific invoice for the customer tax status to something else, then change it back. When this field is edited, the tax for the invoice is recalculated correctly.

You may also be able to fix this by running the Data Integrity Check, and if the incorrect batch total is found, running the Rebuild function will correct it. If you choose to do this, make sure you back up the data prior to running these functions.

The date problems may be due to your date settings in Windows, or to the original batch total problem. Make sure that the date format for your Windows regional settings uses the YYYY year format.