T5HO 24" vs. 36" vs. 48"

[OttawaFolkFestivum]

I found this post interesting:
http://www.aquariumpros.ca/forums/showthread.php?t=23934

Is it common that 36" T5 fixtures have less output (per unit length) than either 24" or 48" fixtures?

[Hookup]

The article goes into a theory, not detailed or proven, that the 36" bulbs are putting out more photons than the 24" bulbs but doing so over a greater surface area.  The idea was proposed that if you could capture and measure "all" the photons leaving the 24" bulb and compare that to all the photons leaving the 36" bulb the 36" bulb is putting out more.  This idea was based upon the fact that the meter has a small sampling surface area even when compared to 24". 

A second unproven theory was that the same ballast for the 24" bulb is used in the 36" bulb which might represent an over-driving on the 24" or an under-driving of the 36" bulb.  It is reasonable to assume that to keep manufacturing costs down overall, some parts are re-used between systems.

However, then end result, for the bulbs/systems tested the 24" 10000k's packed a punch that was greater than the 36".