[Elecraft] K2 Filter Setup CW vs CW Reverse

[Ben Hofmann KB1AHR]

I've been playing around with the filter setup in my
K2 S/N 4429 to get them to my liking.

Has anyone had any luck getting the difference in
pitch between CW and CW reverse to a reasonable level.
 I'd really like it to be within 10Hz if possible. 
>From my understanding the factor which determines this
is the accuracy which the original signal has been
tuned in.  I am confident in my ability to zero beat a
received signal against the spot tone, which should
make the tones of the two within 5Hz of each
other(based on the 10Hz resolution of the VFO).  But
even when a signal is zero beat it seems my tone pitch
between CW and CW reverse in the filters is closer to
30Hz.

I've noticed that there is some discrepancy in the
requested sidetone pitch in the menu setting and the
actual spot tone frequency.  I'm not sure if this has
anything to do with it or not.  I get an actual 600Hz
tone when the sidetone is set for 590Hz.  Measurements
made with Spectrogram.

Anyone have any insight, or is this small of a pitch
difference between CW and CW reverse not possible due
to DAC resolution maybe?

-Ben  KB1AHR
K2 S/N 4429