For example here are the updated 2020 policies from another provider with new guidelines on ABA treatment from page 26:
https://magellanprovider.com/media/45694/mcg.pdf
As someone mentioned below it’s highly likely that you may need to have a formal reevaluation and ABA treatment officially recommended.
EDIT - Sorry, the link above is actually the new 2020 MCG guidelines that your insurance provider was likely referring to.