Created attachment 94597 [details]
Asymetry in SUMPRODUCT
SUMPRODUCT function treat empty cells as 1 when the arrays in the calculations in the argument are placed in reverse order, but treat empty cells as 0 when the arrays in the calculations in the argument are placed in the usual increasing order.
Increasing order: SUMPRODUCT($A3:$A11;H3:H11) treat empty cells as 0 in both vectors
Reverse order: SUMPRODUCT(H3:H11;$A3:$A11) treat empty cells as 1 in
the H3:H11 vector but not in the $A3:$A11 vector
*** This bug has been marked as a duplicate of bug 74479 ***