Performing calcuation based off IF formula

I am doing a spreadsheet in which I want to perform different calculations based on the answer entered in a particular column.
This is the scenario-
I have one column that is labeled C/B (which stands for correspondent or brokered) in this column I will enter either a C or a B. Then in the next column I want to have a formula that calculates 0.005*A1 if the value is C or 0.00375*A1 if the value is B (with A1 representing the loan amount)
So what I am wanting the spreadsheet to calculate for me is-
If the loan is Correspondent (C) then the fee taken from me is 0.005 of the Loan Amount
and
If the loan is Brokered (B) then the fee taken from me is 0.00375 of the Loan Amount

I know I can change C/B to 1/2 (1= correspondent, 2= brokered) and do P3=IF(M3=1,"0.005","0.00375" which would give me either 0.005 or 0.00375, then the next column would be Q3=P3*A3
but I was hoping to keep C/B and do the whole calculation in one column.
Any help from the excel guru's would be really appreciated.
Thanks in advance