After much searching, I have determined that the formula shown below is the
reason that recalculation on the named worksheet "All Data" takes up to 6
seconds. Does anyone know why this particular formula could be such a
problem? And if so, is there a substitution that would eliminate the issue?
Here's the formula:

=SUMPRODUCT(('All Data'!G4:L1504<"")/COUNTIF('All Data'!G4:L1504,'All
Data'!G4:L1504&""))/COUNTIF('All Data'!E4:E1504,"Y")

TIA