Formula to sum various cells based on rate factor
 

In cell Y4 I have a drop drop down menu with three selections called A,B,C.

In cell T6 I have a number associated with A
In cell T7 I have a number associated with B
In cell T8 I have a number associated with C

In cell F12 I have the same drop down menu with three selections called
A,B,C. and in its corresponding cell G12 I have an input cell for a number.

In cell H12 I have the same drop down as in F12 and a input cell at I12.

This relationship continues for J12/k12, L12/m12, N12/O12, P12/Q12, R12/S12.

In cell T12 is my cell where I need a special formula to total all the
inputs based on several criteria.

For example if F12, H12, J12, L12, N12, P12, R12, were all A and Y4 was A
then T12 would be (G12*T6)+(I12*T6)+(K12*T6) and so on.

However if any of the inputs in F,H,J,L,N,P,R, are B or C and Y4 is set to
A, then those input cells that are not based on A would have to be converted
to A in the sum.

For example if Y4 is set to A and all the cell selections are A except say
j12, which is set to B, the sum of the row at T12 would be every A reference
times T6 and J12 times T7.

I hope I have sufficiently explained this. I once saw something somewhat
similiar that was based on scripting instead of cell formulas.

Thanks for any help offered in this challenging problem.