The array formula was extremely useful and I am trying to edit it for the
following:

Gaps sheet is where account and meter info is kept, along with periods
(months) that have already been reported.

Main sheet is where new data is kept. Want to be able to delete the rows
where the periods (months) have already been reported.

Gaps!A3:A10 = account #
Gaps!C3:C10 = meter #
Gaps!E3:E10 = reported periods
main sheet, cell A2 = account #
main sheet, cell F2 = meter #
main sheet, cell P2 = period that this billing data is for

=INDEX(Gaps!$E$3:$P$10,MATCH(1,(Gaps!$A$3:$A$10=A2 )*(Gaps!$D$3:$D$10=F2),0))

Should I be using a different function or are my operators incorrect? What
am I missing? HELP!!!