I'm presuming they wrote that before the pics without the cover came out because its got 18 missiles, the S2 radar & the turret section seems to be notably lower volume than either S1 or S2.The Pantsir-SA seems to be fitted with the same weapon station as the Pantsir-S1 which consists of twelve 57E6 surface-to-air guided missiles and two 2A38M30-millimetre automatic guns developed from the two-barreled 30mm GSh-30 gun.
I'm wondering if there is less volume due to no guns/ammo &/or newer better electrics or just relocated into the front section?