Assuming your flight is on time, it should be enough. Keep in mind the distance between customs and the Tropic desk is measured in feet, through the door and you're at the tail of the Tropic line. Also, the schedule is loose. You get checked in and if you are on time for your scheduled flight, you may not necessarily get on it. Quite often people who didn't quite make their original flight are at the head of the line for the next one. If you have a res, you will get on a plane in the order in which you check in. At the end of the day, everyone is in AC. If you get in earlier, you could get on an earlier flight. Works out fine, so just relax and don't worry too much about meeting schedules.
On a separate note, we observed a situation last Jan. where a Maya flight kept calling for a passenger by name for boarding. He never showed and the flight left (for a mainland destination) without him. He showed up about 15 minutes later (I think he was a German kid, his English was limited, and he had been on the phone with his sister, who was awaiting his arrival). It was late in the day, no more flights to his destination, and he had packed virtually all of his money in his checked luggage, which was on the departed plane (kids, what can you do?). Maya ended up (very polite and concerned, gotta love these people)cabbing him into town, putting him up for the night, and scheduling him on the first flight out in the morning.