Why loosening torque is lesser than the tightening torque for bolts/screws
the mathematical answer would have to lie along those lines:
while tightening, you are working against increasign resistance
while losening, you are working against decreasing resistance, one you are over the hump, bingo your screw is lose.
the same hump in footpounds while tightening doesn't yield any observable results (free movement) as it runs against drastically increasing resistance.
Now, who has the math for this ?