I also own a 190 (aswell as far too many other Rover 75's & a ZT-T, all KV6's apart from one 1.8) & as already said, the 260 just plods along (if you want it to) at such low RPM, it's just effortless.
I love all my cars & the it's fair to say, even my 190 just pulls itself along without having to thrash it.
I guess a lot depends on how a driver tends to drive as to how slow (or fast) the fuel gauge drops.