Thanks for the clarification. The original assumption was that the higher voltage would give the same power output, with a lower current (and thus allow smaller wires/traces). I didn't even think about the current threshold of a transistor (although I should have), or the higher voltage making the transistors run hotter.
This class isn't supposed to delve into electronics this deeply, but its hard to avoid when we're troubleshooting hardware and trying to explain why its not working.