I would assume so. Ultimate isn't a completely separate program, it just has a lot more awesome features I think FXhome will emulate the system they did with Effectslab and Compositelab updraging to Visionlab Studio. Better wait for one of the officials to confirm.
There will indeed be an upgrade option being implemented soon, although we don't have it in place quite yet. Those bits of the site should be finished soon though. Keep in mind that the upgrade cost will probably be slightly more than the exact price difference between the Standard and Ultimate versions, because it has to cover the expenses of handling two transactions. Not a huge amount more, but a bit.
Looks like there is no option to upgrade or to see what an upgrade from Ultimate to Studio would cost just says no products are registered that are eligible for upgrade