=IF(INDEX(EmployeeMaster!O:O,MATCH(H2,EmployeeMaster!A:A,0))="Y",IF(SUM(Y2:AD2)>=SUM(S2:X2),0,IF(SUM(S2:X2)>15000,15000*12%,SUM(S2:X2)*12%)),0).
This formula is intended to work as follows.
IF SUM(S2:X2) - SUM(Y2:AD2) >= SUM(S2:X2) * 12%
THEN RESULT
ELSE 0
Also H2,EmployeeMaster!A:A,0))="Y"...