I want to start a family plan with Tmobile. I want to purchase the samsung galaxy s4 with 150$ down and 20$ per month for 24 months plus the plan, and an Iphone 4 with 18$ down plus 15$ per month plus the plan, along with two other $0 down phones. However their site says that the first line is 50$ second line is 30$ and every other line is just 10$, so can I choose the order of which phone I want to be on the first line, second line etc. because If the samsung galaxy s4 is first then the I would need to pay 70 per month but if it's my third line I would only pay 30$ per month. So I just want to know how this works, will I be able to choose which phone I want to be first???