Hi,
I have a P800 and I get the full range of standard paper sizes in inches, including 13 by 19. The A and J series are also there, but at the bottom of the list.
It may be a matter of System Preference – Language and Region. Go to ADVANCED, and choose US for Measurements units. I had the same or similar issue with the printer or maybe some other program where I could not get the imperial/US measurements showing. That was fixed once I chose my region as Canada and set the Measurements Units to US.The default measurements units for Canada is Metric, so you need to change that. I am on a MAC.