question about dynasty!!

when I simulate one game in the Playoffs,my team has taken a commanding lead finally,but I also have to simulate the OT ,Why,what's the problem???

forgive my poor english!!!

There's no problem, it just means during the simulation your team lost its big lead in the fourth quarter resulting in an overtime period.

let's speak numbers... a 20-point lead isn't that large (had a nice 9-27 quarter once myself)... but there might be a problem if say a 40 or an even bigger lead gets blown away

Well the only problem in that case would be the random nature of simulating games which is unavoidable if you're completely simming games. The only way around that is to play the game so you're not leaving it up to chance.