I'm always leary of this kind of product. Why wouldn't the manufacturers of the batteries just incorporate this "secret ingredient" into their batteries to start with?
So you pour some oil in that floats on top of the water acid mix. How much time could it be in contact with the Oxygen and Hydrogen as it bubbles off in an overcharge? It does not seem like you'd be able to recombine those into water effectively.
I suspect there would not be much difference and although it's patented someone would be using it if it was cost effective. Three times longer means a 15 year battery. That's not happening.
Every US Military motorized vehicle that has a battery either has one of these installed is or going to have one installed. My brother's company won the contract to make these things...