Adding new condition to IF statement

Please accept my apologies in advance - I have a good knowledge of excel, but I have been handed a project to continue and some of the formulas included in it are far beyond my current capability.

My current formula reads as;

=IF($F6="YES",IF(OR($BR6="AP",$BR6="APT",$BR6="AP + ARP",$BR6="APT + ARP"),(IF($T6="SHEET",$AC6,$AE6)^INDEX('Lists&Variables'!$E$130:$E$149,MATCH(CONCATENATE($BR6,$T6),'Lists&Variables'!$C$130:$C$149,0),0))*INDEX('Lists&Variables'!$D$130:$D$149,MATCH(CONCATENATE($BR6,$T6),'Lists&Variables'!$C$130:$C$149,0),0)/60,0)*IF(OR($BR6="AP + ARP",$BR6="APT + ARP"),2,1),0)

This was not written by me, but I now need to expand the formula to include the following;

If K6="ASSY", calculate the formula using cells AC7 and AE7 OR AC8 and AE8 (whichever is the largest) instead of AC6 and AE6 (If K6 = assy, cells AC6 and AE6 will remain blank and results in a #N/A result).

Is it possible to do this without putting all of this into VBA?