I don't have a preferred source for Tersa knives yet.
My chrome set (that many say are just for softwood) have retained their basic sharpness far longer than I expected - the finish is good, but not as good as the HSS, so I assume they weren't as sharp, but the hardness of chrome kept them sharp longer. I plane all my rough lumber with the chrome set. The HSS set gives a better finish, but is dulling faster, and far more subject to dings - probably sharper but not as durable.
I have wondered if I could "tune up" the HSS set with a stroke or two with a diamond hone, while they are in the machine. Not sharpening enough to remove measurable steel, but just a "touch up." I do have a mark on the knives so that I know which is the first side and second side of each blade - that would also help keep the three knives in my set the same if I honed one side of the three knives.
If you try honing, let us know how it works.