This is not from the real manual... It even has spelling error in it. Is this how the game models the aircraft? If so it is very unrealistic and undermodelled. Eyeryone lets stop guessing and rather present facts shall we?. Manuals for both F-15C and F-15E are publicly avaible and declassified.
The real performance from the manual(1993 updated version with PW-229 engines):
You can clearly see that top speed at standard day clean aircraft with CFT is mach 2 not 1.6! And this is also at structural limit of the CFT. That is a huge difference in speed.