If you are explaining this right caster CANNOT get worse or by that I mean "higher numbers." Caster in this light means the amount the top ball joint tilts BACK giving you MORE positive caster. So if you move the ball forward, that will be "less."
Sorry by worse I'm meant more positive caster. The highest number we saw and stopped at was 6.7. I can't explain why, I just saw what the machine was saying.