Newbie: What percentage of hands do multi-table players play?

[evensteven]

Have this newbie question about how to play several tables:

Don't get mad at me now, because I am only curious.

Is the "main reason" that multitable players can play 4-12 tables and still make a profit, that they play only a very small percentage of their hands?
(And thereby really only play one or two tables at any one time, but with much better hands?)

Is this how it is done?

(OK, I also know there is skins, programs and tools that can help. There is good articles about those things here at 2+2. I do understand that with experience comes good judgement and fast decisions)