Hustler Sport owners manual says change oil and filter every 40 hours (but then says refer to engine owners manual for maintenance schedule...Kaw engine owners manual says to change oil every 100 hrs. and filter every 200 hrs. Can anyone tell me which it should be? I live in Florida and mow well kept residential lawns. Not much in the way of dust or dirt but it is hot in the summer time. BTW - I've never posted to a forum before and I couldn't find any way to search the forum for this topic. If this has already been addressed and you can link me to the answer that would also be great. Thanks!