@You Gene The way i see things, MDS informed Smyth Research that their boards will be discontinued likely at some point in January. They sent them samples of the new boards. SR needed some time to adapt the firmware to the new hardware and the new features coming with it (mostly the 24 channels). That could explain why there was pretty much no shipping in February.
Even though MDS can still send the previous boards for a few months, Smyth Research decided that it was smarter to switch right now to the new models and propose straight away an enhanced A16. However, they still had a certain number of old boards in stock, which represents quite some money, so they couldn't afford to throw it away and replace them with the new ones. Consequently, they decided to continue shipping A16 with the old boards till they ran out of it, and only then to inform customers of the changes and that's why they said that the modifications were effective immediatly.
Note that i don't actually know if that's what really happened, but it's the way that would make sense to me.