I've got a series of Excel 2007 sheets that are opened via a different application (Waters Vision Publisher [VP], to be exact). For some reason, sometimes these sheets will open with Automatic Workbook Calculation set to Manual instead of Automatic. I suspect that there's something to do with VP here, but I can't be certain.

Is there something in Excel that, on open, would turn this off? Is it a setting I can tinker with? It seems that those sheets that are heavier on formulae are affected more often, but there's not a very strong pattern (via user, workbook, or Excel version) that I can determine.