I have a Scag Wildcat with 61" deck, about 54 hours now. Great machine. I noticed the last couple of times that the some of the time the cut quality of the center blade seems not quite up to the other 2. Granted, I take advantage of the speed of the machine and mow fast, but up to now the cut has been pretty much perfect. I notice this slight problem mainly on very fine paster grasses and sometimes an entire dallis grass on johnson grass stem is left standing, only in the middle. Today I changed out the blade and the bolt but frankly it is not always noticeable so I don't know what the effect of that was yet. Looking under the deck and rotating the center blade and watching the end of the blade against the deck housing at the back, it varies by maybe a quarter inch - that is lower on the deck straight back and higher on both sides. Both ends of the blade do the same thing and the blades that I have tried seem straight. I have hit a couple of stumps, one of them dead center (killed the engine) when the mower only had 7 or 8 hours. I replaced the blade then since it was nicked, and the bolt was stripped out, but I have not noticed any cut quality issues and I have changed out the blades twice since then. Could this be a bent spindle? The deck does not appear to be bent, and is so thick I think it would be hard to do. The mower still cuts bermuda perfectly smooth and clean, it some of the pasture grasses that it is noticeable on.