That's true, if Marner successfully gets an OS that
he is willing to sign then that team didn't make that offer based on Marner using Matthews as his comparable,
but rather at what price point they thought they could steal him away from Toronto at.
Both the
bolded conditions above must be true.
Because Marner is also not going to sign an OS for less than he believes he is worth so Mitch is still using Matthews indirectly in that process when he is setting his asking price from another team. The other team doesn't care as to how he arrived at his price point, they're only concerned at what price point they can successfully force Toronto not to match it. There are no player comparables involved at all just the $$ and draft pick compensation levels in this decision making process.
Leafs would instantly match an OS at $10.5 mil not because they like the $$ nor the term, but because the 2 X 1st + 2nd and 3rd round picks would not be enough to let him walk over. So Marner and his agent know $10.5 mi X 5 year OS is the bare minimum he would sign, which guarantees him + $2 mil more than Aho OS $8.5 mil just got.
However if another teams really wants to steal him away that means their # must be >$11 mil or more, to have any chance of success of the Leafs walking away and taking the picks instead, because that OS $$ amount is too much to fit into Leafs own internal salary cap.
So his $11 mil to resign with the Leafs because of AM and JT OR $11+ mil is his OS asking price he is willing to sign. However as far as Mitch is concerned he didn't need to use Matthews as a comparable to get his $11 mil or > AAV OS but he still ends up at the same end point regardless.