What firmware are you running??
Mine seems to be OK on xmit but several hundred Hz off on rcv. I'm thinking it might be the constants used in the firmware for the USB & LSB offsets. They're used by the firmware to calculate the freqs for CLK1 for a given dial freq. The BFO freq (CLK0) also will affect the actual tuned freq. AFAIK, the only way to change those CLK1 constants is editing the firmware source.
CLK2 is the only one used on xmit and then it should be the dial freq +- 800 Hz depending on sideband selection.
At least that's how I understand it from wading thru the firmware source (I'm running the CEC v1.11 firmware).
Mine also seems to change slightly as it warms up and it also does not seem to track linearly...if I get it spot on for, say, 14 Mhz, it's off at 7 Mhz and vice versa.
