When two family members have one account but different plans I think they should be allowed to share the total data of the two plans instead of having to pay extra when one goes over the limit and the other only uses half of the monthly data usage.
Shared functions have been brought up before. The way it's looking, it won't happen for awhile. The phone that uses half the data...set up a wifi hotspot so when the other phone is close by, it can use that data. For now, that is the only other option.