87.1°W SES 2 C/Ku101.0°W SES 1 C/Ku103.0°W SES 3 C/Ku105.0°W AMC 18 C
I Also note the bands - C vs Ku. AMC-18 is a C-band only satellite. C-band is used in more professional applications, like TV distribution to cable companies, NOT direct to home, so that reduces the number of receive stations you've got to deal with (by orders of magnitude).
SES was formerly known as SES Americom, the merger of (you guessed it) SES and [GE] Americom. The SES-x satellites came from the SES side, and the AMC-x satellites came from the Americom side. So when they talk about moving customers between those satellites, they are doing it because they own those platforms, not because they are colocated.