I'll explain again why all the above effort to determine who has the better rates is flawed.

WR1 + MU1 + RP1 = SR1
WR2 + MU2 + RP2 = SR2

where:
WR = wholesale rate
MU = markup
RP = retail percentage
SR = statement rate
1 = American Express
2 = MasterCard

We know the variables in bold, but we don't know the WR and MU figures. Therefore a comparison is impossible, particularly as WR1 and WR2 could differ significantly, even on the same trade date.