It is very important to make sure you exhaust your pressure canner for the proper amount of time. Most are usually for 10 minutes. The All American says to exhaust for 7 minutes. Always follow what your manual recommends for the canner you are using.
If you don't exhaust the canner for the right amount of time then the inside temperature may not correspond to what is on the pressure gauge.
Take that extra few minutes and stay safe.