Assuming that in A2:C5 is a table of data,
Why is it so that these two worksheet array formulas give different
results:
1) {=SUM(IF(OR(($A$2:$A$5=value1);($B$2:$B$5=value2)) ;$C$2:$C$5;""))}
2) {=SUM(IF(($A$2:$A$5=value1)+($B$2:$B$5=value2);$C$ 2:$C$5;""))}
and only the second one gets correct result (summing C2:C5 only if
A2:A5 has the value of value1 or B2:B5 has the value of value2)
I'm not sure but it looks like the logical function OR in the array
form
does not translate to na array {t,f,f,t....} but to a single {t|f}
value, but
(($A$2:$A$5=value1)+($B$2:$B$5=value2)) translates to an array of
{t,f,f,t...}. Am I right ? Why is it so ?

Thanks
Tom