It's not just the CAA fees it's the weeks of loss of earnings attending the courses that ramp up the costs. I'd be amazed if a new AME would even break even...
Not to mention the fact that you need to pay annual registration fees and have your premises inspected, and presumably pay medicolegal fees as well. You'd have to be doing dozens a year to make it financially viable, even after the training costs were amortised.
http://www.kcl.ac.uk/lsm/research/di...ectus-2015.pdf