The WSJT6 "Rate In" and "Rate Out" numbers normally need to
be set just once.  (If you change sound cards, do it again.)
Otherwise, you can generally ignore the displayed numbers.

If the displayed numbers wander around, it is MUCH more
likely that, for some reason, the Windows clock is updating
in an irregular way.  If you see no warning messages in the
WSJT6 console window, it's very unlikely that there is
anything unstable about your audio sampling rate.

If your system allows you to set "Sample Rate Conversion
Quality", set it to maximum.  (In Win/XP, go to Control
Panel -> Sounds and Audio Devices -> Speaker settings ->
Advanced -> Performance.)

Also, if your Windows version offers "Performance Options",
set "Processor scheduling" for best performance of
"Background Services".  (In Win/XP, go to Control Panel ->
System -> Advanced -> Performance -> Advanced.)

-- 73, Joe, K1JT