Does anyone shrink/felt their new knitted wool covers on purpose?

[JessieBird]

Just curious because everything I have read says to be oh so careful when washing knitted wool covers so as not to felt and shrink them but I've never read exactly why to avoid this and all I can guess is the obvious decrease in size, which can be overcome by starting out a few sizes big. Desperate for a solution for my two super-soakers who leak out of everything within two hours of going to bed at night, I bought a couple of Disana covers (my first time trying wool pull-up style covers, though I have used wraps with varying degrees of success). They looked huge and floppy so I deliberately used hot water when I lanolized them then I - gasp - threw them in the dryer for about fifteen minutes, then let them air dry the rest of the way. They now fit much better and they are the most effective night cover I have ever come across. I'm not even putting that much padding inside (prefold with one hemp booster) and both my guys are totally dry and happy for 10 hours overnight now - this is a HUGE milestone in our household!