Is there any adjustments for side to side height? I have the self propelled 21" model. The total height adjustment is quick and easy, however the mower deck isn't level and results in the mower scalping on one side. Am I missing something? Also is there anyway that the speed of the blade can be increased? The.mower does a much better job when it senses a load condition that causes it to speed up. The resulting cut and mulching is superior to what is produced at the the normal operating speed?