tonight I was flying back to my home airport and descending from 5500’ about 10 miles out to the North. I called the tower in the Class D airspace and told them inbound full stop. The ATC said to cross midfield and make left traffic for 27R. The TPA is 1600’ so I descended to 2600’ to cross mid-field. The ATC snapped at me and said I needed to be at TPA to cross. I quickly descended but this brings up my question. I seem to remember from training that you cross midfield at 1000’ above TPA to avoid crossing any airplanes on the downwind. By crossing at TPA I crossed straight thru the downwind traffic on the north side of the airport.