[Elecraft] [K3] KAT3 algorithms?

[Randy Moore]

I am puzzled by how my KAT3 is working.  (FW 4.39/2.73)  Just now, I was 
chasing some DX on 20m.  I was listening on 14.020 with split up to 
14.022.5.  I called once and noticed the SWR was up around 3:1.  That's 
ok, but I wanted to get it down a bit, so I killed split, moved VFO A 
down to a clear frequency near 14.018 or so, and hit ATU TUNE, which 
produced an SWR of 1.0:1 at 5w.  Then I used my spotting program 
(DXLabs) to put me back on 14.020 split 14.022.5 and called again.  SWR 
was back at 3:1.  I repeated the process and got the same results 
again.  So then I went up to 14.023 with VFO A and did he ATU TUNE, and 
all was well with the SWR at 1.0:1 transmitting on 14.022.5. So then, 
using the TUNE button, I check the SWR back down at 14.018 and it was 
1.2:1.  So, why was the original ATU TUNE at 14.018 not good enough at 
14.022.5?

After going through the tuning process at 14.023, I can no longer repeat 
the original process.  everything in the vicinity of 14.020 +/- 5kHz is 
1.2:1 or less.

Is there a description of the KAT3 algorithm somewhere?

Also, I've wondered how the ATU memories are allocated across bands, and 
how many there are.

73,
Randy, KS4L