There are several things we fellow forumites do not know. We do not know how you ride, what you weigh or how light a seat tube your bike has. You are not likely to damage the post unless you are going to subject it to extremes. But if you are heavy and hit a hard frost heave at speed and you are riding a very light frame, you could dent the seat tube at the end of the post. If you are riding a very light modern steel frame, you might want to consider a longer post just for peace of mind. I have a Campy (Courus) areo post. Nice posts, but they are not long. There are lots of longer nice posts.

Ben