Still the norm in Oceanic Airspace, which incidentaly is Class A above F55, to indicate that a FL nearer to that originally requested may be available at a particular point along the cleared route, e.g RLCE 55N020W.
Doesn't come into RT fail procedures which, as for most things Oceanic, differ a fair bit from those of Radar environments and controlled vs uncontrolled airspace.
Rgds
T3