I've always regarded these quoted speeds to be maximum speeds rather than minimum speeds, i.e. max clean would be 240 down to approx. 210, At the OM it would be max 160, (sometimes requested by ATC), down to, say, 125kts.
In a heavy B744 freighter with a max landing weight of 302 tonnes the bug speed would be in the region of 157kts, speed at the OM would probably be not less than 180kts, we always advised ATC of our intended/requested speeds though, since we tended to be outside those published in the Jeppeson.