Bids are given precedence based on sort order of Price, Quantity, and then Time placed. If you bid $50.00 on 50 units and someone else then bids $50.00 on 100 units, that person will be winning for all 100 units. If you then raise your bid to $60.00 for 50, you will be winning 50 units (at $60.00) because your price is higher, and the other Bidder will be winning 50 units at $50.00.
Bids retain the time when they are placed. Because we use time to break ties, if you placed a bid for the same Price and Quantity as an earlier Bidder, the other Bidder will win. It is to the Bidder's advantage to get an initial bid in as early as possible. However, if the Max Bid is raised later, the Timestamp is changed to reflect the new bid. We recommend that you make your bid using our Automatic (Proxy) Bidding functionality.