If you'll look ... you'll find "that" on lots of reloading data, not just on your two examples.
What I was trying to say... that you have two different testers, from two different labs(test facilities),different test equipment. They used two different guns to arrive at their test data... so may be one gun could tolerate more pressure than the other or gave a different pressure altogether. Then you have the different bullets ... one may be of harder lead or harder jacket material, just because they weigh the same don't mean they are the same.
It no different than two cars built exactly the at same, one tops out at 130 mph the other 120 mph. One get 13 mpg the other 15mpg.
That is the reason that they say to start 10% below Max and work your way up until you get to a safe point for your gun ... not mine gun, but your gun. If I use Hornady bullets, I use Hornady data, if I use Serria, then Serra for starting loads. I may to other data after I have found their data to be safe in my gun.
Clear as mud!
Jimmy K