"Paul B." wrote:
I have read through most if not all the previous posts on
conditional formating, SUMIF, etc...but I am no further ahead.
[....]
I need to write a formula that will take the value of 'A'
and if 'A' is greater than 2, subtract 2 and multiple the
remainder by 2, then add 3.

Part two or that same formule will say if 'A' is equal to
or less than 2, simply multiply by 1.5
[....]
Now, one more thing. If possible I would also like to
vary the formula based on 'B' being either 'R' or 'D'.
if 'B' = "D" then the entire amount of 'A' would be
double time. If 'B' = "R", then the formula needed
above would apply.

Not quite sure what this has to do with SUMIF(). Does
the following meet your needs:

=IF(B1 = "D", 2*A1,
IF(B1 < "R", A1, IF(A1 <= 2, 1.5*A1, (A1 - 2)*2 + 3)))

Note: I am guessing what that if B1 is neither "D" nor
"R", you simply want the value of A1

As I have written it, this formula would go into some cell
other than B1 or A1. Does that match your intent?