T5 lighting question.
 

Regarding different lenghts and "watts" of T5 bulbs

48" bulb has 54 watts
36" bulb has 39 watts etc.etc.

Can one assume that at the same depth you would has the same intensity of light directly below the bulb from any T5 bulb?

When you say "intensity" are you talking about usable light? Hopefully you are because radiant flux makes my brain hurt.

I am, I'm assuming the increased watts is due to bulb length and that an inch of 24",36" or 48" bulb puts out the same amount of usable light.