Not quite.
There is an adjustment to fatigue made before the playoffs start to take all pitchers and hitters up to say 98% fatigue, even if they were under 98% previously.
If you went over, you will not be adjusted.
Essentially this means that you will get more out of a pitcher in the post season than you would during the season... But don't think of it as 10% or being entitled to say 24 extra nnings from a 200 IP starter, because it doesn't quite work that way.