Note that Max is the $100/$200 per month plan; In addition to the obvious incentive to upsell, I suspect attempting to use Fable on the $20 per month plan would wreck your quota.
On a related note, Codex just reset their weekly quota, again.
Now if they could just extend the 50% weekly limit increase promotion which will otherwise expire on July 19th at 11:59PM Pacific, they might actually remain competitive.