I've tried it with all options selected, with just priority mail selected, with just the priority mail flat rate box options (all of which say "international" next to them), and none of these give me the continental us priority mail flate rate box shipping option.
So, once again I ask, are the USPS Priority mail flat rate boxes for continental us missing from the USPS shipping plugin?
I am going to System > Shipping Methods > United States Postal Service (Hikashop USPS Shipping Plugin)
It is simply missing the USPS Priority mail flat rate boxes (small, medium, & large) for shipping within the US. It does have them for international, but as 95+% of my sales are in the US, the international option doesn't help.