I have received emails from a couple of different MSCs, advertising their open scheduler/editor positions. I haven't typically seen information on their websites.
Last year, I worked for several months as an editor for one of my favorite MSCs. The hours were way more than what you would expect, it took too much time away from shopping, and the pay worked out to be far less than minimum wage. They did warn me that the pay would be very little in the beginning, but I never imagined I would sometimes be working for $1/hour. I hung up my editing towel and went back to just shopping for them.
As far as the actual position, it was what I expected. I'm educated and I am a good writer, so that part of it was easy. Sometimes you got reports where the shopper was clearly English ASL, used a voice recognition software (and didn't proofread), or just plain didn't follow instructions or read the questions. Those ones were horrible to edit. Especially when I'd have to contact a shopper for more information or return the shop to them for corrections because the MSC is very lenient and allows DAYS for shoppers to finalize the returned shops.
There's also a learning curve regarding how the particular MSC wants things worded or spelled. Like writing "AM" instead of "a.m." or knowing exactly what they want in the descriptions of the employees. Also, learning the guidelines on how the shopper should be graded was tedious. It doesn't seem like much, but there are a lot of rules to follow.
Maybe I would consider editing or scheduling at a different point in my life, but right now, when I often make $20/$30 hour shopping, it's not worth my time.