Live bid amounts are even. You cannot bid $2400.99 live. If you prebid that amount the system will only allow you to make the next acceptable bid during the live auction - which it shows you. You do not enter amounts during the live auction (takes too long and is error prone), you only press the button for the bid amount shown on the button. You will then see your bid in the running total. You will then see any subsequent bids higher than yours, should there be any, and gives the chance to press the button for the next acceptable bid amount. They do about 100+ lots per hour so individual lots do go pretty fast.
There is also an option to show the max buyers premium for a bid amount. While I too would prefer if the bid amounts included the buyers premium I am not aware of any live auctions that do not work the same way. The bid amount goes to the seller. Even Christie's charges a buyers premium on million dollar paintings.
