If you take a look at the attached photo, you will find that the plan did specify 398 Leopard 2. The title of the slide says MBT Leopard. Admittedly it didn't actually say whether it's Leopard 1 or 2, but the actual negotiation is specifically for Leopard 2.Just to clarify, my understanding of the 400/3XX + tanks does not refer to Leopard 2 or MBT. Rather it is just an overall planning number, which can be and is supposed to be met by a combination of Medium Tank and Leopard 2. There does not seem to be further plans for additional acquisitions and the possibility appears low for now.
The photo was supposedly taken during a Pussenkav (Cavalry Weaponry Center) presentation in 2011. At the time they already downselected the Leopard 2 out of the usual candidates.
Of course, just because the cavalry wants that many MBT doesn't mean that they will get them. You are correct in that there is currently no plan on getting more and that the probability of further acquisition in the near future is low.