My attitude is that salary is "sunk costs."
Since Hextall has cleared enough salary room to have flexibility, on ice play decides whether a player is in Philly or Lehigh Valley. However, overpaid players are easier to waive, so that's actually a strike against them (hey, they can always volunteer for a pay cut if they don't want to ride the bus). You can stash them in LHV as injury insurance if they get beat out in camp - and that is a big motivational tool.
Given the Flyers depth, both MacDonald and Lehtera produce or sit, rregardless of their contracts. The contracts only enter into Ron's decision making when it comes to transactions (buyout, pay half to move them, etc.), but shouldn't factor into PT.