If flights run to their schedule there's no problem with stand allocation, problems arrive when you have 744's arriving 45 minutes before schedule (In which case, what's the point in a schedule)?
Favourable tailwinds can often lead to early arrivals, especially (but not exclusively) north Atlantic eastbound.
There are several variables that effect travel times, it's not just the weather and winds.
Congestion and delays at airports have to be factored into schedules hence the "block time" generally being much longer than travel time.