Thanks Norie. I already had both of those turned off.

I was just doing some more experimenting and discovered that the lag exists even when I manually rename the range from within Excel. When I go to Formulas > Name Manager and resize the range, I get about a 2-3 second delay while Excel grinds away making the change. This does not happen with most of my other named ranges, so it must have to do with the 1000+ cells that are referencing this range elsewhere in the tool. Presumably they must still have to update - even with the spreadsheet set to calculate manually.

It sounds like I should be looking to those cells for a better way to calculate/reference, rather than the macro - which seems to be fine.

Thanks for your help, everyone. I'll report back with any new findings.