FFlowers, I seldom play after 8 pm (hungry husband), and I can tell you that they will raise the minimum at a table consistently getting a lot of play, which usually starts in late afternoon. But they are good to grandfather.
Since you were playing well into graveyard, did they ever LOWER the minimum? When we walk through going to breakfast around 7:30-8 am there aren't a dozen players total at all the tables, dealers standing in wait.
As for not counting a second buy in, I always make sure the boss knows when I've bought in again (not my husband, though...LOL.