Absolutely not, but I don't think any of these things are mutually exclusive.
I think Ovechkin knows that once his quality of play has slipped from the NHL level he can "retire"without overstaying, like he's alluded to, and still go on to play in the KHL and be effective.
Simply because of that, I don't think he's speaking of Dynamo Moscow as a ceremonial last game type of thing. I think he wants to play there when he's done with the NHL, whenever that may be, but not when he's done with hockey. If he has 1 season to give them he'll do it, if he finds he has 4, he might do that. It won't matter either way because I don't think it will come at the cost of NHL years, but the guy is a tank and if Jaskin can light the KHL up you have to think he's got something left for them beyond a cheap game or three.