After spending more than 90 minutes yesterday in the lounge the First/Business bus never moved. The bus behind it which I thought was also a First/Business bus did leave and then I saw it was the "VVIP/VIP" bus. Both of those buses only have one door per side for passenger loading/unloading, which is in the rear of the bus. Normal buses have two doors per side, one in the rear and one in the middle. Being there's apparently only one of these buses and it didn't move during that time and lots of the normal buses did, I assume it doesn't get much use and First/Business passengers are probably normally just loaded into the normal buses but with sometimes separating business from economy passengers.