Just traded the 500 for a 530 and this is my 1st tractor with a hyd. deck. Is it better to lower the deck after use or is it OK to leave it in the up position. I noticed the system must bleed down some as if the mower sat awhile it lowered on its own about an inch. Did not lower while under pressure when mowing for 45 mins last night so I'm sure it does not leak. Thanks.