^What extraO said s pretty much right.
A lot of the jackets I've seen fit like that. I have a 686 Havoc jacket and it fits how you described yours.
I personally like it going down that far, because when I'm in the park I put the tailbone pad into the back of my slam shorts (don't tell anyone!).
That friggin tailbone pad adds a little bulk and makes my rear end look... kinda large.
But the long length of the jacket actually covers it completely and after comparing in the mirror, looks exactly the same as it does without the bulk of the tailbone pad.
So if you wear slam shorts in the park or wherever, that's the kind of fit that you want to have.
In my opinion jackets look better that way anyway; and they keep your backside a little warmer when sitting on the chairlift or if your one of those guys who sits down to strap in.
Now if your real name is Shaun White and you usually like to a wear low-cut leather thing that look like a thin motorbike jacket from a strip club, then no, a long and normal jacket is not for you! (No offense if you're a fan.)