How are you managing with 13 channels?

Actually, that's not really true at all. You have an egg carton with 6 eggs in it, the other 6 being empty. Does cutting it in half really save you any time taking eggs out? in the end, they're still all in the same carton.

You can't look at it in that way. Every channel have monsters in it, moving the monsters around, giving out the information to users (where characters are, and where the monsters are). By cutting the amount of channels with (as in your case) 50% would cut the amount of memory needed to run the program by 50% (well, ignore horntail and zakum for now, please). It would also cut the processor-power-need, but not by exactly 50%. True enough, you don't have to calculate where the monster's going to be in the channels recently removed, but you still need to drag in info from characters in a map and deal it out to all other players in the map. Stores drain processor-power (and memory) more than characters itself too.

tl;dr
You have a chicken-farm. The chickens eat earthworms, but they can manage to eat the amount of earthworms a day on half the area you have. If you cut the size of the farm, you'll have more control over the chickens, and have to cut less grass (if you even do so).