I've never tried CYA removers but we keep it simple here at TFP. Drain/refill is still your best option.
This concerns me:
I'm still pretty new here myself, but I was attracted to this site by the fundamental tenet of TFP's do it yourself philosophy. Never trust anyone else's analysis. We are naturally, and rightfully, skeptical of pool store or pool company assertions. They are in it for the money and their sole intention is to sell you products you don't need. Get yourself a TF-100 kit and test the CYA yourself before proceeding. It's really easy once you dive into it and the community is here to guide you every step of the way.
You might want to do a change out of another 20% of your water and retest it when your test kit arrives.
Report back here when you're ready.
Lucas