In the sense that a good reflector will allow you to utilize more of the light being generated by the bulb, yes. So if you're on the borderline for light levels needed to grow a certain plant, then adding a good reflector can possibly eliminate your need to add an additional bulb.
i just started my first planted tank, when i ordered it i told the owner of the LFS that i needed 3-4 watts per gallon, thats not what i got. he said the reflective strip would be fine for a high light tank. now i think he was mistaken. i only have 80 watts for the tank.but it is bright with that reflector.
You can add another strip, retrofit the existing fixture with 2x55W or 2x96W bulbs (ahsupply.com), buy a whole new fixture (Jebo sells a 4x55W for $60) or overdrive your current fixture. All-glass also sells a tripple T8 fixture for little more than a twin strip, my first choice would be to return the existing fixture, seeing you were wrongly informed by the seller, and exchange it for the tripple. I have the tripple on a 90 gallon and it is very nice IMO.
Overdriving was the cheapest solution for my 55g, at x2 it's equivalent to around 3WPG: