Can Family Plan Member be Converted to Own Plan...

....without termination fee?

I'm one year into a two year commitment, that includes the main
account and three other family members.

I just added another family member last Saturday, and accepted a two
year commitment to get the phone free. I assumed that this meant that
the commitment clock on the main account began fresh at two years
also, because if I were to cancel my main account before two years,
the new family member would no longer have a main account to which to
attach itself.

The salesman told me not true, that the main account's commitment
clock doesn't change, and that if I were to cancel the main account,
the new family member would only need to become it's own main account
to avoid a termination fee.

I don't know if this is true, because one year ago, when I re-signed
for the current two year commitment I'm in now, with the three other
family members, I was told that all three family members had to stay
on the main account for two years, and couldn't convert to their own
plan.

Who's right? I can't find it in the contract.