Just because it was an offersheet doesn't mean it was inflationary, everyone was shocked at how low it was
Every offersheet attempt to steal is designed so the original team will not match and you get the player so its an overpayment by design. The goal of any successful offersheet is not so the original team gets their own player a fair market value, while you waste your time helping other teams get their players under contract for them.
Carolina his own team certainly wasn't willing to give Aho that, but matching was better than the comp picks, so their hand was forced to accept the contract another teams GM signed your player to.
If this were an arbitration case for Marner he couldn't even use Aho OS total as his comparable as the CBA even states that directly as inadmissible, because of the understood inflationary nature of that process of that other CBA tool usage.
If Aho and Marner are seen as close comparables despite Seabass being a centre which are valued higher than a winger. Then Leafs paying their own player willingly more than another teams offersheet attempt to steal amount by intentionally bidding up an opponents contract, that would be the definition of an overpayment.
One of the major deterrents of an offersheet usage is the future fear of retaliation.. Not much fear if defending one gets your player signed at fair prices by matching it.