Hi -
I'm having trouble trying to figure out this formula sent from a coworker. I'm told I should be using it but of course that person is on vacation for 2 weeks... Does anyone know what this bad boy does?

=SUM(OFFSET('2015 Invcd'!$A$1,MATCH(A96,'2015 Invcd'!$A:$A,0)-1,2):OFFSET('2015 Invcd'!$A$1,MATCH(A96,'2015 Invcd'!A:A,0)-1,MATCH($B$1,'2015 Invcd'!$1:$1,0)-1))

Thanks