I have read countless descriptions of HEPA being described as filtering 99.977% of particles, BETWEEN 0.3 and 0.5 microns, and countless descriptions of it described as filtering 99.977% OF 0.3 micron particles.....and sometimes both in the same article. I don't know what the standard really is, but the details aren't terribly important to me, because what I do know is that HEPA grade filters are extremely well respected for helping people out with dust sensitivities, allergies etc etc etc.
There's a reason why doctors recommend that standard for helping conserve people's respiratory health, even before you have respiratory problems. They should be clearer about where they get the MERV rating....I expect it was evaluated at the same time as the particle fraction, but they don't say.
I'm not sure what you mean by throw away, and I can't see that in documentation associated with the Oneida products. Are you inferring that because they can be damaged if abused in some way? Well I suppose an armored tank is throw away too if it gets abused enough. If by throw away you mean it is not repairable, then as far as I understand you're right. But I think you are suggesting that because HEPA filters are not cleanable, and Oneida says theirs are, then that must mean the Oneida filters are not HEPA? It's my understanding that in many applications users just don't bother to clean the filter (and the manufacturer would sell more if you don't), not that they are non-cleanable. I expect because of their very fine structure, they are sensitive, and they would prefer people not try to clean them and screw it up, but I've never understood them to be absolutely, categorically, without a question uncleanable. Oneida does give us some careful instructions for how to clean theirs, and sells an SP meter to show when cleaning is required......they also say that eventually you will have to replace it. Would an Oneida filter be killed by planer chips hitting it when your single stage gets overfilled? I don't know, but it's an excellent question I didn't think of.