"variable rate" = prime plus %
The multiple rates they showed is saying that depending your your credit, you will get one of them. 3 tiers of prime plus a number for that term.
If you can, the best way to understand CC interest rates is to not revolve a balance. If you have to revolve a balance, assume the worst rate and have an exit date for when it will be PIF.
IMHO when and if the new CC law takes effect, it will be a bumpy road interest rate wise until the smoke clears.