Yea I don't make much money as an editor. see: http://www.articulateventures.com/thoughts-on-being-an-emplo...
ALSO, I'm sure you can hire someone on craigslist to give your work a second read for gramatical mistakes, if that's really a blind spot you care about.
But I worry, are you even trying to get better? It sounds like you've accepted your current skill level as a fixed balance that can't improve, when that's probably not the case.
But I'm curious then: do you currently do the grammar editing yourself (in your "Fixer" package)?