If you have a single ref in charge of the process, then of course it will be "different times" (unless he could juggle doing both teams @ same time. Given that it only took the officials 9 minutes to gauge the Pat footballs...the "different times" line is really a joke.
Different conditions? Outside? Inside? (No)
This is basic: you need to use the same devices. Time is important when you are dealing with the “ideal gas law”. Conditions are important if the balls are at different temperatures....when you are dealing with fractional changes in PSI, time & conditions are all that matters. You have no understanding of what you are talking about.