Ya know, if GP3 was GP2.5, then if you're saying GP4 is GP3.5, then it is half as much of GP3 added onto GP3. Which means GP4 is actually GP2.5 + 1.25, which is GP3.25.
Hang on I have done something wrong.
Oh, I is GP3.5, not GP3 and 1/2 of GP3, so it is actually saying that GP4 is really GP3, (GP2.5+0.5)
I think that's right.
Skywal_ker
P.S. My head hurts bad now...