The makor concern that I have is just because a display shows that it is 464 or any other numeric value, does not mean that is what you are actually getting!
A while back, MZap reported about a competitors machine ( digital something or the other ) had an almost 3000 percent error. Most of the message posted had to be redacted because of a threatened lawsuit. Regardless of the truth or fairness, lawsuits can be destructive.
The company did their best to imply a relationship with Dr. Clark and also supposedly was operated by some M.D. in the U.S. but it turned out to be fictional information.
I am not pointing fingers at any company in particular, but I suggest that we all need to remember the phrase 'caveat emptor'.
If you have access to an accurate 'frequency counter', I suggest checking your unit out for accuracy and resolution. Any good local electronics repair service should have a technician that would help you for free in their spare time.