Well I bit the bullet and tweaked the 0x86 register on one die.  I tried a few different values, 0x0168, 0x0068, and 0x01ff.  initc did not seem to throw any errors, and everything hashed like normal.  I did not notice a difference in power consumption on any of the settings, so I can only assume the hash clock was not affected.

So ... there goes that theory.