various rates

The review revealed that the GOOD, to EXCELLENT, documentation of the swim teams who use our pool on a daily basis, started 6-11-08, and continued until very recently. There are apparently various rates for different pool rentals- 3-12-08 pool rental $180; 5-3-08 pool party rental 1-5pm $97; 5-10-08 pool rental $ 77.50; 5-19-08 and 5-26-08 rental $123.40 each; 5-31-08 rentals $172.60 and $ 130.00. Anybody know what these various rates may be for? Did somebody out there say they rented the pool last Summer for $240? What was the date on that check? When was it cashed? More pieces to the puzzle..