You do know that AIN doesn’t work like that right
Tank is the default AIN and healer can only be AIN specifically when tank isn’t AIN
So if you are looking at the levelling roulette and there are 30 parties that are looking for a healer, if even one of those parties is also looking for a tank then tank will be AIN despite there being a far higher need for healers
It’s why at the dead of night when nobody is queuing tank is always just the default AIN
lucky’s census for the end of EW shows there is about 1.2 million with capped healers and 1.7 with capped tanks so healer is definitely the rarer role