I seem to recall that M2 steels requires a fairly strict heat treating regimen.  One of the laminated M2 blades for one of their other planers says something about being treated in a vacuum chamber.  If I had not already added a Shelix blade to my 735, I would definitely consider getting an aftermarket set of blades for it.  I think that Infinity makes one and I have seen others as well.  

I know that the OEM blades are not supposed to be sharpenable but here is a video that seems to indicate that you can get a couple of sharpenings.  I'd probably give it a try, if they aren't too beat up anyway.  

--Nathan, TX. Hire the lazy man. He may not do as much work but that's because he will find a better way.