if those measurements are in feet then he may be right. otherwise thats the biggest load of rubbish i've ever heard. my tank is 101 x 41 x 50 cm (in the pic below) lighting cost £56 for the 2 extra tubes and ballasts on top of the original 2. even if i had no lights to start with that would be £112 plus £40 for reflectors.
if i were you i'd print off this topic and take it in to the shop armed with a big stick to bash him with.
talk about stop you in your tracks, what a XXXXXXX that makes me so angry
Edit: granted your tank is slightly larger but not by that much and as depth is the biggest problem mine is deeper than yours so he's talking rubbish. good luck with the tank