Quick protein gel electrophoresis question

Hi all. My question is: in Isoelectric Focusing, considering the equation for migration velocity v=E*z/f , is the reason that the lower pI proteins travel faster toward the anode and higher pI proteins travel faster toward the cathode because the "z" is of greater magnitude (but opposite in sign) for very low pI compounds and very high pI compounds?

Let me know if you need me to clarify anything about my question it might be a bit confusing.