A2:A5 = 100, 200, 300, 400 respectively.
B2:B5 = 5, 15, 30, 40 respectively.
A1 and B1 are both blanks.

=SUMIF(A2:A5,"300",B2:B5) yields 30. Okay.

I know I shouldn't do the following but if I have a typo, I prefer Excel to give me an error ......

This is confusing.

=SUMIF(A2:A5,"300",B1:B2) yields 15. ??? B1 = blank and B2 = 5.
=SUMIF(A2:A5,"300",B2:B3) yields 30. ??? B2 = 5 and B3 = 15.
=SUMIF(A2:A5,"300",B3:B4) yields 40. ??? B3 = 15 and B4 = 30.

I rather have an error telling me of uneven range.

Any comments?

Epinn