The owners manual I recieved with tractor was for 20r series and said 1.2 gal for 3 cyl engine later I got a manual for the 3510h tractor it calls for 1.4 gal. but if i put in almost 6 qts dipstick shows overfull by at least a qt. I'm confusted as to why I got a 20r series manual with a 3510h...