My understanding of when flight time starts is when all doors are closed, the brake is released and ACARS trips the out time. The clock stops when the A/C is parked at the gate and MCD is opened. At my company our pay is based off of the MCD but the in time is tripped by any door but usually the cargo door trips our in time. The problem is this. Usually the rampers open the cargo door and beginning unloading the bags but there is no jetway driver to drive the jetway so we sit sometimes for a couple of minutes or many. Sometimes there is no GPU available so the #2 engine will be up until the GPU is available or I crank up the APU if it will be longer than 5 minutes or so, which is rare. The companies stance is that the time that we are waiting is paid as flight time but they are not counting it against our FAR flight duty limits. I believe this to be wrong. In just the last couple of pairings I have 27 minutes of flight time that the company is not counting as flight time but is being paid as flight time. Anyone care to give their opinion and if this is happening to them.