I believe visits are counted not per player, but per amount of times visited. I mean that if your game counted each player once, it would be 8 people, but since it’s counting each of you separately, your game will have about 400 if each of those players visit about 50 times.
Long story short: Roblox counts every time a player joins, not every time a NEW player joins.
Everytime someone joins your game you get a visit and it doesn’t matter if the game is Private or Public. Visits are not counted per player but rather how many times they join the game for a while even if it’s Developers or Testers joining