First it appears that the "Adwords Day" runs 7am to 7am UK time. (Please let me set MY business day here, not Google time)
As I monitor the impresisons during the day (even accepting that the monitors may be 2-3 hours behind, I see an apparently slow slow start to the Google Day. Projecting this into the future there is no WAY I will use my daily budget.
When I wake up and check at 7am the next day, miracle of miracles, my budget is all used up.
Whether it is fact or not, I perceive that the impressions are not evenly served throughout the day, but are ramped up as the day passes.
This means that I perceive that impressions are skewed (perhaps) away from timezones that I really want as customers.
OK, I can also see how I may be incorrect here. I just wanted to air the feeling and see if I am a lone voice.