PPP: Player Position Preference

Is there a difference between two players who prefer the same position but in a different order? In my observation, players tend to list their most defensive positions first (left), and their most offensive position last (right)(i.e. AMC, ST or DMR, MR)

Normally I would have a screenshot but I can't do that right now so here is my example.

P1: DC, DMC
P2: DMC, DC

Now, P2 is newer to my squad. He was originally listed just as P1 (DC, DMC). After his first game or practice he got a training point and assigned it to his Defensive abilities. When I clicked Ok, his "PPP" flipped to read what it is now: DMC, DC. Why would this occur?

P1 may have originally been a DC because his SA is Defensive Wall. P2 was likely a DMC first, as his SA is Playmaker.

Does this mean P2 will perform well in both but favor DMC? Or will any player be equally fit for whichever role they are in as long as it's in their PPP.

For the record, coincidentally, I purchased P1 to play DC, and P2 to play DMC. Both were Q59 but I based the decision on their SA's.