Oops! A typo! The right formula is here

=SUMPRODUCT(--(Sheet1!$A$2:$A$100<=A2),--(Sheet1!$A$2:$A$100(A2-7)),--(Shee
t1!$C$2:$C$100=B2),Sheet1!$D$2:$D$100)


Arvi Laanemets