Thanks for posting this, it's actually one of my favourites from the early days. I'd say "Pathetico" is a bit of a blasphemy in its own right, he's usually pretty successful up until the point that Spirou & Fantasio get involved in his plots.
I do know that they're living together in Aux Sources du Z (which does a nice tribute to this volume), so perhaps that apartment bit in Machine Qui Reve was an attempt for Tome & Janry to rewrite that bit of their history, as with Seccotine's name and so forth. Which was all tossed out as a bad idea when the next crew took over, although it wouldn't surprise me if they were told to do so from on high.