These links will give you a better idea of the specs and buoyancy characteristics of HP and LP steel tanks. A HP100 is 9 lbs lighter than a LP95, same length, virtually the same buoyancy characteristics:
http://www.xsscuba.com/tank_steel_specs.html
http://www.divegearexpress.com/library/tanks.shtml#dimensions
Chronically overfilled tanks fail from metal fatigue, a gradual weakening of the metal from stress. The farther over a tanks’ rated fill pressure the more stress on it.
The pressure on a tank underwater is insignificant compared to the pressure from within the tank - 1 atmosphere = 14.7 PSI - you’d have to go pretty deep to equal 3600 PSI, so the water pressure is not going to prevent a tank from failing.
There is some inherent risk while diving which we all accept, otherwise we’d be playing croquet. Why add an unnecessary factor?