You have to talk to your insurance people; it's not a "law" of any sort, it's just what they have decided to do/a new "standard" and some insurances/doctors are doing it and some not.

90 minutes sounds like 2, 45-minute sessions, back-to-back, to me, I use to pay, out-of-pocket $190 for 100 minutes I remember. I'd go once a week instead of twice a week.