Are you sure you want to save invoice totals? It's generally considered bad practice to store calculations. Primarily, you have to consider that if a figure used in the calculation changes you might find the old data reflects new values when it should not. If you correct a price for a line item, the stored table value will be wrong for that line - unless you design to enforce a new calculation. For all the trouble you can get yourself into, it's just better to perform calculations in queries and/or forms only.
EDIT:
are you using calculated fields or data macros in your db? I think nobody with version 2007 can open a few of your tables.
also, to help with deciding on storing calculations, suggest you read http://allenbrowne.com/casu-14.html
Last edited by Micron; 11-25-2017 at 10:08 PM.
Reason: added info
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