Can I avoid the 90-day reporting requirement by leaving Thailand every 90 days on a non-imm O-A visa?

As predicted here, the option of a multi-entry, non-imm O visa (over 50, retirement) is no longer available at the London Embassy. I am now looking into a multi-entry, non-imm O-A visa instead.

I have a couple of questions. If I left Thailand every 90 days, would I be excused the 90 day reporting requirement? At what point would I need to buy a multiple re-entry permit for my second year, on my last exit of my first year, or can I buy it in advance?