[Elecraft] K2 - power out

[N2TK]

A question about power out with my K2. I really had never paid attention to
it before, so there may not be a problem.
On the low bands, 40, 80 and 160M I get a little more than 100W out when set
for 100W.
On the other bands except 17M I get 98-100W out when set to 100W.
On 17M I get 80W out when set for 100W. The voltage measures 13.0V key up
and 11.8V key down on the K2's display on all bands when set for 100W.
I made sure C32 and C34 were peaked - no difference.

Any ideas or is this normal?
Is my voltage dropping too much?

Tnx,
N2TK, Tony