Average & eliminating zero value Need HELP !! PLEASE
 

In cell C4 im calculating average hours for D5:D65 of all employees
In cells Z5:Z65 If L is entered means laid off
In cells AB5:AB65 IS AVERAGE OF ALL EMPOLYEES HOURS in cells D5:D65 if L is
entered in Z Column
In cells D5:D65 IS all employees hours

FORMULA FOR C4 IS
{=AVERAGE(IF(ISNUMBER(D5:D65),IF(D5:D650,D5:D65,0 )))}

Formula for cells AB5:AB65 IS
=IF(Z5="L",R4,"")

Formula for D5:D65 IS
=IF(Z50,0,IF(B5="","",AA5+SUM(E5:J5)*1.5+K5*2))

I want to average all employees hours except if L is entered in Z Column so
say 65 employee hours if L is entered i want to calculate THE OTHER 64
EMPLOYEES HOURS FOR THIS EMPLOYEE & Yes there will be zero values only in
column D5:D65