[Elecraft] [P3] Another symmetry question

[Fred Jensen]

I have a K3/100.  For CW and RTTY below 10 m, I normally run a 20 KHz 
span with the ends of the span on even 20 KHz boundaries [3500-3520, 
3520-3540, etc].  I'm in Fixed Tune mode where the span edges remain 
fixed and the VFO cursors move as I tune.  Tuning off the edge results 
in a full 20 KHz shift [IAW, a new 20 KHz span].

When I change bands using BAND UP/DN, the P3 seems to preserve this 
configuration from band to band.  The same seems to hold when I use 
direct frequency entry.  However, when running N1MM+, typing a frequency 
into the call sign window will go to that frequency on the radio but 
will put the span edges at odd 20 KHz boundaries [3510-3530, 3530-3550] 
and sometimes at 3515-3535.

Does anyone know how the P3 recalculates the span edges on band changes 
from an external control program?  If I knew, I might be able to compensate.

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County