I'm struggling to create a formula which sums Column C IF (Column A = [name]) AND (Column B = "Possible" OR "Proposed" OR "Committed").
SumIF column a = X AND column b = Y OR Z
With some functions, e.g.
SUMIFS, you can get away with referencing entire columns with no detriment to performance, though not with functions which operate over arrays, such as
SUMPRODUCT, and any construction requiring
Use SumProduct with as the or operator rather than * as the and operator. Something like this:
=SUMPRODUCT(($A:$A=[name])*(($B:$B="Proposed") ($B:$B="Possible") ($B:$B="Committed"))*($C:$C))
You can try the following formula
=SUMPRODUCT((A:A=[name])*(((B:B="Possible") (B:B="Proposed") (B:B="Committed"))