Other scenarios can influence the use of "when level fly speed..."such as 2 a/c descending on speeds to be level by a particular point. This could be a standing agreement between two sectors or co-ordination with next sector or centre. Many a time i have had a call to reduce speeds ...ie 250kts by next sector mid way through the descents. The descent profile and current speed they are operating on means an adjustment in speed would end up with them not making their level. Being level in todays enviroment is crucial in most cases.
So.. "when level fly speed..." is a logical answer to this as they make the level and the speed for the next controller.... although........I have never had to use min speed :-)
055166k hope slam treating you well...place not same without you