Applied your suggestion...seems to work like a charm.

I've set it to write "Manual" on my Hidden page before the Application.Calculation = xlManual. That way, all the formulas on my other page have the chance to adjust before it switches to manual.

Sheets("HIDDEN").Range("F6").Value = "MANUAL"
  Application.Calculation = xlManual
Then, set it the other way around for automatic.

Application.Calculation = xlAutomatic
  Sheets("HIDDEN").Range("F6").Value = "AUTOMATIC"
Looks like all the pages are reacting well to the change, which was what worried me.

Lockin' this now.
Thanks for your input, consider yourself rep'd.