AMO changes Bids twice a day ( mid- day and mid night). In the new release there is an option of changing bids 2 extra times called as intraday bidding.
Hope this helps!
After clicks and revenue models are run, AMO compute right bids for keywords, these bids are pushed to search engine at midnight 12am. A second round of revised bids may be pushed at noon to accommodate any budget changes 12pm.With new intraday bidding, AMO retrieves, data for google clicks and cost at two extra times per day (08:00 and 16:00) update cost and revenue models based on trends and then set bids.