A blood processing system , wherein said blood processing system comprises a centrifuge , and wherein said centrifuge comprises a first port and a second port , said blood processing system being configured to execute a method comprising: introducing blood into said centrifuge through said first port ; separating said blood into a plasma layer , a buffy coat layer , and a red blood cell layer within said centrifuge and by rotating said centrifuge; executing a first monitoring step comprising monitoring a location of an interface between said buffy coat layer and said red blood cell layer within said centrifuge; executing a second monitoring step comprising monitoring for an existence of a first condition and a second condition; said first condition requiring: 1) an amount of said blood introduced into said centrifuge being both less than a target processed blood volume and within a first predetermined amount of said target processed blood volume; and 2) a determination by said blood processing system that said interface is in a first position from said first monitoring step; said second condition being said amount of said blood introduced into said centrifuge being larger than said target processed blood volume by at least a second predetermined amount; and directing a fluid flow out of said second port of said centrifuge and into a first container , wherein said fluid flow comprises buffy coat from said buffy coat layer, wherein said directing a fluid flow step is initiated in response to said blood processing system having identified an existence of either said first condition or said second condition, wherein each of said first monitoring step, said second monitoring step and said directing a fluid flow step are executed by said blood processing system. introducing blood into said centrifuge through said first port ; separating said blood into a plasma layer , a buffy coat layer , and a red blood cell layer within said centrifuge and by rotating said centrifuge; executing a first monitoring step comprising monitoring a location of an interface between said buffy coat layer and said red blood cell layer within said centrifuge; executing a second monitoring step comprising monitoring for an existence of a first condition and a second condition; said first condition requiring: 1) an amount of said blood introduced into said centrifuge being both less than a target processed blood volume and within a first predetermined amount of said target processed blood volume; and 2) a determination by said blood processing system that said interface is in a first position from said first monitoring step; said second condition being said amount of said blood introduced into said centrifuge being larger than said target processed blood volume by at least a second predetermined amount; and said first condition requiring: 1) an amount of said blood introduced into said centrifuge being both less than a target processed blood volume and within a first predetermined amount of said target processed blood volume; and 2) a determination by said blood processing system that said interface is in a first position from said first monitoring step; said second condition being said amount of said blood introduced into said centrifuge being larger than said target processed blood volume by at least a second predetermined amount; and directing a fluid flow out of said second port of said centrifuge and into a first container , wherein said fluid flow comprises buffy coat from said buffy coat layer, wherein said directing a fluid flow step is initiated in response to said blood processing system having identified an existence of either said first condition or said second condition, wherein each of said first monitoring step, said second monitoring step and said directing a fluid flow step are executed by said blood processing system. <EOS>