bidders can use the incremental bid  up their max,  or  go 'all in'   with a single  bid  that  could leap frog any  unused max bids still in play.   


Not sure,  but I think if the current bid is  say 30,000,    they could  jump in with a  33,000 to start,  then also back that up with  a max bid of  say  35,000... but In this case,  it looks like the winner  just fired off single bids.