Sample AttachedSimple Sample.xlsx

What I would like to accomplish is having all the values summed up by their function by month.

EG: Function 1 (ZZ) = 14 for Jan
Function 2 (ZY) = 10
ETC...

The problem is I would like to have the ability to add more Tests and functions and have it all summed on another sheet when I add more.
I was thinking of using IF statements and VLOOKUPS but I don't have the eye to write it efficiently.

Any help would be greatly appreciated.