No, with the 5S you could change the $360 medium tab to a small tab.
With the small tab the $360 now becomes $120 upfront and $240 on the tab. In which the $100 trade in could be applied. Leaving you a balanced $20 plus tax to pay immediately for the phone cost.
Also by moving from $15 monthly cost on the medium tab. To $10 monthly on the small tab.