Releasing early is not just a cost issue. I used to take pride in releasing from aerotow in the first good thermal, below 1,000 feet or not. But at our gliderport, landing back and waiting for the queue to clear in front of you on a good day can take an hour or more depending on how many training flights/rides are stuffed in. Doesn't happen often but the penalty when it does is severe.

Chip Bearden