Your right the game time wouldn't matter but rather the commerical time. I think this is where MLB rights would be worth a lot more than NHL since there are only 3 commercials per period in the NHL vs MLB which is after every half inning. A lot of NHL ad time is in intermission when a lot of people either change the channel or go do something else. In terms of total time this site said 42 Min of Ad time for MLB and 30 for NHL.
If the rights were on the open market I'd take the over $125 in a heartbeat. I'd have to think TSN and SN push the number over the estimated market value just to get the contract kind of like the NHL. Kind of moot since it won't happen as long as Rogers is owning the team but its fun to dream on.