The QuadraCut blades were not the ones pictured. The ones pictured were the Microcut Twin blades....those are the ones on my HRX. My HRR has the QuadraCut blades you described (see pictures).
My HRR blades---QuadraCut Blades.....<img src="http://www.lawnmowerforum.com/attachment.php?attachmentid=14906"/>
My HRX blades---Microcut Twin Blades......side view: <img src="http://www.lawnmowerforum.com/attachment.php?attachmentid=14907"/> from underneath: <img src="http://www.lawnmowerforum.com/attachment.php?attachmentid=14908"/>