I would think that more than a few would have trouble interpreting the word 'Now' as meaning unrestricted.
Heard this more than once on London frequencies, the clearance is questioned by the aircraft usually with "confirm unrestricted climb"
and normally receives a rather curt reply from controller.
ICAO are making a real mess of the climb/descend phraseology on SIDS and STARS. Personally I would like to see the same
methodology that is applied to take off clearances, ATC shouldn't even mention the word climb or descend until you are actually able to
do it, conditional climb or descent clearances are not the way we should be going.