From what I have read recently, from CPA to Rev Share is not a problem, but Rev Share -> CPA looks suspicious. There was a thread where an AM shared a scam with CPA pulled on him, and a few more joined to share their experience as well.
Most mentioned that they research well a website that wants to do CPA too.
I’ve never tried the CPA model, but I can’t really see how it can be more profitable than rev share for an affiliate.
Regards,