This is also an odd parental stipulation. Basically they are offering you more for Penn ($56k) than for USC ($36k) or Temple ($30k), but nowhere near enough to make it affordable, as if they are trying to tempt you with something that is out of reach, while also making it more difficult for you to afford USC or Temple.
If they offered you $56k for USC, you would need to cover only $16k, while if they offered you $56k for Temple, you would only need to cover $4k. Either of these is more doable than the options that they gave you.