I'm not sure what is going on there. Most of the NHL talking heads seem to have very little insight into the Adams' front office thinking and report from a standpoint of what others tell them they've asked for from Buffalo. Adams may not be Regier, but there is not a lot of idle information that spills out. As to the why, I would speculate that they want to sign him but have started to squeeze themselves with some of the other long-term deals. Also, for Mittelstadt, he can point to his production relative to other players on the team (namely Thompson and Cozens) this year and rightly state that he has similar or even better impacts than those two so he'd be looking at something in the $7+M AAV neighborhood. I don't know if they want to go there even if he's outproducing the other two, maybe they do.
Mitts is one of the guys who the is ringleader for some of the now younger, single players who live near the lake front. His place is where they congregate and he's tight with Dahlin (whose condo it was they shared prior to Dahlin moving out to his new McMansion in the suburbs).
At points this season Mittelstadt has gone into Thompson's spot between Skinner and Tuch and got both of them going and now that Quinn is back on IR, he's centering Cozens and Cozens is having his best stretch of the season over the last few weeks (overlapping with Quinn's return and subsequent ankle injury). He's their leading scorer at 5-on-5 this year and over the last two years, even with Thompson in that regard. I would think they would like that flexibility I just wonder if they think they're going to eventually have to pay Peterka and Quinn and are hedging their bets early instead of just trying to get him signed to a value deal now and worry about those other deals later (you know, like most winning teams do).