i do apologize in diverting this thread from the op question. i guess what i'm getting at is the actual hours on your engine can depend on the type of tach/hr meter you have. in my own mind i would rather know how many actual real time hours are on my engine for maintenance purposes, rather than hrs based on rpm @ 540 pto output. as pointed out, this may not make a difference in fluid changes, or regular maintenance etc. however from my pt of view, it is something to keep in mind esp when buying used tractors with say w/2000 plus hrs on the mechanical meter. that's all.... just to keep the discussion at a peaceful level 