Three VSOT VOAs have been posted here in the past and each was significantly different. We need to get a big jug of oil and divide it up to send 5 samples each to each of 4 or 5 labs and see whether the variation within a lab is any better than the variation between labs. Whichever lab had the lowest internal variation would likely be a best bet.
I have a feeling VSOT has been dumbed down. It used to have loads of goodies, but now it looks like it's not the same. Probably still pretty good product though, just not like the old.
where are you at in the U.S.? If your by me I would let you use one of my samples for OAI. It's not worth the cost to ship a pre-paid $15 kit. But oai is good.