I understand this might not be the ideal way to run without sales orders, but currently we just use Invoices to be our Work Order (traveler in our mfg shop) and then we change the template to be an invoice and then change the date when we invoice it out.  Has been working fine for many years.  I'm guessing when I enable advanced pricing something changed.  We had to do a company wide price increase (due to the rising costs) with all of our products.  I have old Work Orders (invoices) that we've finished and want to bill out.  As soon as I change the invoice date from whatever it was to something different, poof all of my items with base rate pricing change to match that.  Doesn't matter if I change the date to older or newer. Even when I had overrode certain prices on a ticket. 

Is there any way to disable this automatic price change once and invoice is done, regardless of date changes?  I've searched and looked through all the preferences and can't seem to find it.