I assume you're using compact fluorescent bulbs, but you tell me...incandescent, fluorescent, compact fluorescent, HID, LED...or what? also, what is the color temperature of your lights?
"its good for veg"...that all depends, on the type of lights and the color temp, and the distance from the canopy, and the position...hooded or not. over 4000k, color temp, is good for veg. 6500k is great.
not necessarily stronger, but it wouldn't hurt. more bulbs would help grow bigger, denser buds. the color temp is most important...and the total lumen output. flowering MJ needs under 3000k for best results. I use 2100-2500k, HID lights.