I know a few friends and people on SU who have older fair and flexible plans and free and clear family plans that added a data pro pack for $30 and were able to use the pre...In fact telesales told them that was the requirement n it worked...

I have a unlimited family share plan I added the pro pack on my line and it wont let me online or by esn swap on phone....

There has to be some rhyme or reason considering i have with my very own eyes seem people with same plan and similar older plans with pro pack using this phone