"You can play all day with all the credits you want, but you still
can't get a score past your skill level."
MANY years ago I took a Tempest back to Milwaukee and left it with
some friends with my high score. I said that anyone that could beat
the score could have the game (it was set to free play). I ended
up getting the game back a couple of years later with my high score
still there!
As Zonn said, it doesn't matter if it's on free play or not..