Your violation was for not being clocked off 10 hours before punching back in and driving. That part of the warning letter is justified.
It is likely you were not driving after 14 hours...paperwork etc at the end. But at this point I would make sure you are clocked off in 14 for a while.
You are going to have to make sure you have 10 hours off or you are going to have major problems. You will be considered ineligible to cover DCAP if you don't have 10 hours between punches.