Post Character Limit Inaccurate?

I’ve noticed this a few times while making lengthy posts here. The character limit is 7500, but you can’t go right to 7500.

I think it tells you you’ve passed the character limit when you have about 50 characters left.

I don’t imagine the character limit is reached all that frequently, or that this issue is even that established, but I’ve found it a bit annoying when I do get tight on characters.
I’ll finish the post, relieved that I narrowly avoided having to scale back what I said. But posting prompts me to delete some of it anyway, when it clearly shows that I have 20-30 characters remaining.

It gets especially annoying when quoting lengthy posts, as you don’t necessarily want to delete some of the points you’re addressing, and shortening your own posts can cause some of the meaning or purpose behind your argument to not come across as efficiently as you’d like.

Is there any reason behind the discrepancy, or potential fix?