I'm a little confused too, but I'm going to assume that you basically get your gear upgraded if you have it. This was the case with AT3 - 4... I had Mesa at the time, and my Mesa cabs were automatically upgraded to the AT4 versions. So I'm not sweating that.

I'm not sure why the recommendation for SE in your case, but going by the chart, I guess with the "Amplitube 5" upgrade, you'd be getting the newly introduced amps and whatever effects that are being newly introduced.

I have a bunch of gear credits still, so I'm probably just going to snag a few of those new ones a la carte. But still really glad to hear that they're doing the same thing with cab upgrades like they did with the AT4 rollout.