isnt that essentially the same thing? i mean when they average the grades if you have two 4 hour credits of an A + C / 2 = B. i mean its just how averages work.
The only difference would be in your quality points. A 4 unit class would be worth 12 points if you averaged in one B versus counting quality points for both grades 24 quality points basically worth 2 B's. If you have 200 quality points it's not as big a deal. If all you have is your prereqs it could be somewhat more significant.
2 4 unit classes, 1 A, and a C replaced by an A would then average out to would be 3.5 (1 A + 1 C = 1 B, 3*4 + 4 * 4 = 28, 28 points/ 8 units attempted = 3.5)
The same 2 classes, but all three grades calculated ( 1 C = 8 pts, 1 A = 16 pts, 1 A = 16 pts = 40pts/12 units= 3.33
For two classes with a single replacement it's a 0.17 difference, more classes will decrease the effect, but it'll be non-zero. More replacements will increase the effect.
In my case I only had 22 units calculated through my school, but 24 calculated by PharmCAS, my school calculated 1 D, PharmCAS calculated GPA using both. Hence 3.09 vs 2.86