Random Jackpot

[Cool Hand Luke]

I have a question don't know if it should be posted here or somewhere else so I'm sorry if it is wrong place.Anyway my question is :Howcome a lot of he time the dollar amount never moves until you start playing the game than it starts going real fast? Sometimes if you back out and wait a few minutes it is right back where it started?Other times it goes real fast but these games are real tight.