Adjusting pressure setting and processing time when modifying pressure canning recipe
No modifications are necessary.
The pressure of the canner entirely determines the temperature of the water around the jar, and you don’t start timing until the canner is at that temperature/pressure, so regardless of the scale you’re assured of processing for long enough. In a larger canner and/or a weaker stove the contents of the jars will end up being slightly more cooked because of the longer lag time before you start the timer, but there’s not much you can safely do about that, and for pea soup it will make literally zero difference.