So it seems that adding
chaoswolf's new cell phone to my family plan drops us from unlimited calls between phones on the plan, to 1000. And we have to extend the contract in order to keep our free long distance. The alternative would have been to put the new phone on a new and different (and more expensive) non-shared plan.
I consider this sleazy, but service contracts subject to arbitrary change without notice seem to be the rule these days rather than the exception.