To be eligible for detention, you must be at your appointment on time. I think the best policy on getting detention is to assume any time you've been at a shipper or receiver over 2 hours, that it is possible. As mentioned by others it is dependent on the contract we have with the shipper and receiver - the rate and timing is also dependent on the contract. In some cases you must have the arrival and depart times on the bills to be eligible, and in one case I recall that you have get a time stamp from the receivers guard shack - check the macro 19 instructions and your dispatch data for stuff like that.
Get the seal/time stamp at the company store, stamp all copies of at least one page with it, and enter the times. Its also good for reporting the seal record too. Payroll can get the times from your GPS location data, but its easier if it is right there on the BOL.