@Sticks I don't mean to answer for the guy, but it's pretty clear what he is saying. By possibilty of one person buying all 4 he will look at working a discount on the total. Indicating that the 2500 is not the total of all 4. I really doubt anyone is gona sell 4 x 120w qbs for only 2500 and then give discount too he also mentions that they're brand new... the discount will come in when you take all 4. alternatively if it was 2500 for all 4 then a single would cost 625, which would then be his selling point, though you probably only gona get a flood light for that price. these lights cost a little more than normal lights.
with all that said I might still be wrong