How much boil off did you have with that small of a batch? I'm assuming the 30 min boil is to adjust for this, but wouldn't you get different hop utilizations by boiling less? Also, why the shorter mash, don't the sugars convert the same whether it's 12lbs of grain or 3Lbs?
Not bashing your methods, I'm just curious how this works and how larger batches compare when you scale them up to 5 gallons(or higher). I've been thinking about this lately too and I'm just not understanding the shorter times.