[Elecraft] K2 Low power output

[W8OV]

I recently acquired a very clean K2/100 with external KAT100 ATU.  I 
have a K3/100 and its power output agrees closely with the readings of 
both Bird and Elecraft W2 watt meters. According to these watt meters 
the K2, set to full power of 110W, puts out about 80 - 85 W into a dummy 
load (SWR reads 1.1 on KAT100).  Everything else seems to work very 
well, and manuals came with the radio.

Any suggestions as to steps I should take to get full power output from 
the K2 (S/N 4000+), or is that close enough?

Dave, W8OV