Is there a particular power consumption/+12v power requirement I am not seeing here?
-- mistakeets
There's a power consumption requirement you're not seeing here.
If the 4ms Row Power 30 only supplies 1500 mA on the +12V rail, the lower row is close to 1000 mA. Then the upper row is about 500 mA. If you used just one Row Power 30, you would be very close to the maximum allowable current for that P/S...when in normal operation. Not only is that not good (lots of heat, component stress, etc) for the P/S, there's also the question of inrush current levels at start-up, which would almost certainly exceed the +12V rail's rating for milliseconds. Doesn't sound like much...but it only takes milliseconds of excessive loading to wreck the P/S and potentially cause chaos to anything connected to that +12V rail.
As this stands now, the lower row runs at 2/3rds of the Row Power 30's capability, leaving 1/3rd of capacity as headroom for inrush loads...and this is about right, although you could go up to 1/4th of capacity as that headroom buffer and still be safe. But there's no way that you'd get away with powering BOTH rows from the same Row Power 30 if you factor that inrush into current loading...so, yes, that's actually done right.