Somehow, I don't think our misunderstanding each other is finished. :)

But SUMPRODUCT does sound like the function you want. I think you are
describing array formulas and this function is array by default. The
usual format if you have a variable to check in A, and another
variable in B, and you want to add up numbers in C based on those is:

=SUMPRODUCT(--($A$1:$A$10=x)*($B$1:$B$10=y),$C$1:$C$10)

One thing I'm not following is how copy/paste would come up at all.
How are you avoiding that command?

Also, you seem to be saying you want to sum the results of a
sumproduct "lookup". But they are already summed, that's what
sumproduct does when entered the right way. It can also Count,
strangely enough. So, one formula may be all you really need because
of how it works on arrays. Maybe you should show us the form of your
data and then describe what to do to it.