Alan, yes, I'm, well aware of what they recommend in C2P, but for higher quality Epson continues to recommend leaving it off. From page 96 of the 4900 Manual: "High Speed for fast, bidirectional printing. For higher quality, make sure you deselect this option." Note they say "make sure". To be honest, I'm in no rush so I just leave it off. I haven't blind-tested for quality difference.