Chalmers plays with their great starting lineup.
Cole plays with their horrid bench.
There's your answer.
If that was true, then why does Lebron only post a +21?
Because Lebron plays more minutes than the rest of the starters ... and even HE is dragged down by their horrid bench ...
Food for thought:
Lebron has played 38.4 mpg this year in all 49 of Miami's games - in other words, he's played almost 80% of Miami's minutes. (a little less because I'm ignoring OT games).
Lebron's individual ORtg is a ridiculous 124 points per 100 possessions and his DRtg is 103 (using basketball-reference.com numbers). Which means that for every 100 possessions he's been on the floor, the Heat are outscoring their opponents by a freakish +21!
For almost 80% of all their minutes.
But the Miami Heat's
team ORtg is 112.3 and it's DRtg is just 105.4. For a NetRtg of just +6.9!
Now, +6.9 is still a very good NetRtg for a team. That definitely makes them a contender.
But boy, does that team suck in the ~20% of their minutes when Lebron is not on the floor.
If Lebron got injured - forget it. That team would be toast. Even with him, they aren't a lock, unless Lebron plays 48 mpg.