Yes they are additional seats in a different part of the ground to the away end. The wording is clever though as it says that these additional seats are 'part' of the players' allocation and staff, travelling club staff and VIPs...so they'll also take a load from the allocation for others as well, in this case, from the 1800.
It's usually around 15-20% taken for hospo, players, sponsors and so on...
thats on top of the additional ones they get
So in reality there'll be 1500 ish for normal supporters, club may take less than usual given the circumstances like they do with bournemouth
Anyway, important to remember the same would have happened with Genk and Salzberg and so on, they'd have creamed their 15-20% off the advertised number for them too