Thoughts from a nooby.
30W are included to boost the intensity of the light levels. PAR or whatever term that is being used.
The light set already has a good number of 3W LEDs. But to enable the light to reach the light intensity of a 250W MH, 2x 30W LED are used to replace 4x 3W LEDs from the 110W model. (without the 2x 30W LED, it matches a 110W MH). I would think this is an ingenious idea abeit that it is done in sacrifice of energy efficiency.
The LEDs output is beaming at 120 deg. hence the spotlight effect is not that visible especially when you have 2 at a small distance apart.
But there might be some dimming at the edge perhaps. Digibee has a set and he might be able to comfirm.
imo, the models with 30W LEDs are for SPS.