RE: Eating glow plugs like candy!!!
I'd take a guess it's fuel too and that maybe yours has some water contamination which could explain the difference in tune between what you had and what your friend found he needed. The fact that it's just started eating plugs, presumably on the same can of fuel, also leads me to think the fuel has gone bad. The only other reason an engine will develop an appetite for plugs is if there's some wear going on that's sending aluminium particles onto the plug coil. Aluminium is death to platinum but this doesn't deform the coil.