[Elecraft] freq.accuracy?

[N0SA]

I just added the drift compensation mod to my K2/100, SERIAL #3045. It does
a great job. My drift was up over 100 hz and is now down to around 10 hz.
 The reason for this post is that after I readjusted my K2 PLL and BFO I
notice that I am very close to my other rig and freq. counter on the lower
bands (within 30 hz) but when I get up above 18Mhz my K2 seems to be about
120Hz off freq. Whereas on 18 and below I am wiyhin 30 to 40 Hz.
I was just wondering if this is within reason or should the higher freq's be
closer?
Larry  N0SA