Next to my name it says 500+ posts but I checked and it said 462 posts
Does it usually round up like that?

Maybe some posts that you made were dustbin or deleted, so that's probably why it says 500+

This is a known issue. For me it started saying 1000+ posts when I only had 970.
The most likely solution is what mingo-gag said above.

mingo-gag wrote:

Maybe some posts that you made were dustbin or deleted, so that's probably why it says 500+

This is likely the case…. post count titles update upwards only. I have a bit more than 2,300 posts listed in my posts, but if Scratch counted dustbinned/deleted topics my posts would be upwards of 3,000.