An odd deal - winning the trade (i.e. doing better than an offer sheet) requires either losing the player or overpaying him.
If Hamilton signs for less than $7.3M we overpaid. If he signs for more than $7.3M then we underpaid, but Hamilton might be overpaid. I'm guessing he comes in under, which means Boston won the trade - even if they would've lost had we made a similar offer sheet instead.