I hope others will weigh in, but based on my experience the Inyo permit system (which you appear to be referencing) has two kinds of permits. You get either an overnight permit that allows a Whitney Portal exit or an overnight permit allows exit anywhere else.
The locations on the permit are for entry location. Looking at Recreation.gov, JM22 is for entry at the Baker and Green Lakes trailhead. I think that is up near Big Pine. I don’t know that trailhead, but while I expect there is a way to use it to ultimately access the JMT and then head south to exit at Mt Whitney (assuming you have the Whitney exit version of the permit), that would be a long, multi day trip for sure.
Again, hopefully some experts will weigh in, but I don’t think JM22 is a Mount Whitney permit unless for a long backpacking trip that could potentially exit there.
