I *believe* that
the index number of the sheet... **as long as no sheets  have been
renamed differently** is the same as the number on the end of the
language string.

If *any* of the sheets have been renamed then all bets are off.

It's a question  of consistency. If you upset the pattern then the
pattern is gone.

I know at least one person  who renames all of his sheets in every
workbook prefixing them with a 2 character digit... 01_Summary,
02_Hospice, 03_Patients... and so on.

That can help sometimes but it sounds as though you have no control
over naming the sheets.

Sorry can't help more... Maybe if we get a bit more info on the
application???