Could it be that Central Bank does not bid in "the last second" but before and you can still overbid him and thus bypass?
Would explain this:
http://www.carnageblender.com/gc/view-one.tcl?classified_ad_id=131991
http://www.carnageblender.com/gc/view-one.tcl?classified_ad_id=132036
http://www.carnageblender.com/gc/view-one.tcl?classified_ad_id=132149
http://www.carnageblender.com/gc/view-one.tcl?classified_ad_id=132420