how come?, Efficency on custom maps Options

[Horas]

I saw that there are some custom maps most of the best players have enormous good stats/efficency on. Namely this are mostly Supply Depot 2 and Sw goldrush te. Now I wondered why everyone I see has so good stats on this maps, surely you need less score per minute than in others to be good, but how come? Because there are many other players that really suck on this maps?

Horas