Until I get you some pics, ....are you satisfied that the deck raise handle, it's mechanisms and rods below the seat, the cable lift pulleys, the lift arms, and the cables themselves are in spec? (correct, not bent, not stretched, correctly bushed, and properly routed?).
That the blades themselves are EXACTLY equal distant as measured from the underside of the deck to each tip? (takes out the possibility of incorrect spindles, bent blades, wrong blades, incorrectly installed/sharpened blades, etc.....)
thanks