I think DL overpaid slightly on all three of Muzzin, A-Mart and Lewis, but I think this also shows GM's/teams have a little less leverage with players who file for salary arbitration like them. The team is obligated to take whatever the arbitrator awards as long as it is less than $3.5 million (above that the team can walk away) and those players weren't going to get anywhere close to that. So it's either pay a little more now to avoid arbitration or roll the dice and risk the player getting what he's asking for, which was guaranteed to be higher. Between those three players, I'd estimate DL overpaid by $300,000 to $500,000, nothing huge but in a tight cap year it hurts.
Be interesting to see if Clifford resigns now or not. I think he will, I can't see on what grounds he'd be demanding substantially more than what DL thinks he's worth. Odds are they are only a few hundred thousand apart.