hello -

Thanks to these Groups, I've become quite proficient at using array
formulas to evaluate fairly complex calculations. However, I've run
into a small issue that I just cannot understand and it seems like it
shouldn't be so difficult...

This array formula works fine: ("week" is a Named cell)
{=SUM(IF(ISERROR($M$3:$M$11000),0,$M$3:$M$11000)*( $G$3:$G$11000=($A9&week)))}

This array formula DOES NOT work fine:
{=SUM(IF(ISERROR($M$3:$M$11000),0,$M$3:$M$11000)*( $J$3:$J$11000="C")*($G$3:$G$11000=($A9&week)))}

The difference btw the two formulas is this: ($J$3:$J$11000="C")
The strange part that this formula DOES work:
=COUNTIF($J$3:$J$11000,"C")

Is there some fundamental difference in evaluating a range using an
array formula vs the COUNTIF function?

I've tried evaluating the 'bad' part of the array formula to a VALUE
and to TEXT, but no change...

Any ideas?

TIA,
Ray