(not sure where the crews are coming from?
Easy. LHR and FRA are in the process of being insidiously converted to 3 man crew, the rest of Europe will follow shortly. Layover duration remains unchanged.
TaDaaa!... an extra 10 or more red lanyard wearing crew per day available, courtesy of the HKCAD.
Add to that MOR censorship, probably ASR-F screening, and voila: problem solved. Where's my bonus?