To me, this is now getting into more than a coding question. Medical necessity is the overarching criteria. I personally do not feel that a coder is qualified to override the medical necessity of a service a physician provided.
I'll instead focus on the coding aspect. The time statement is supposed to include the work performed. While what the provider put is not "wrong", there would be better ways to word it. Here's what I recommend to my providers when putting a time statement:
"I have personally spent ## minutes of time today on the encounter excluding any separately billed tests or procedures. This work included: reviewing prior records, obtaining and reviewing history, performing exam, counseling patient, ordering tests or procedures, documentation and care coordination."
I further advise if the time spent seems unusually long to add explanation. Example "Patient had multiple additional in-depth questions regarding activities allowed during the recovery period which contributed to the overall time." "After discussing surgery risks with patient, she was emotional and very concerned. She asked me to call each of her 2 daughters separately and explain the R/B/A of surgery to them as well." Anything that could help explain what could seem like a lengthy visit.
Now let me take off my coding hat and put on my common sense hat. If the patient was returning after a surgery and had NO complaints and doing well and no further treatment, why would it take the provider 20 minutes?? I have my coders work with specific clinicians on a regular basis to help with documentation and compliance moving forward. If you are regularly seeing time documentations that are "suspicious" in your opinion, I would discuss in a very non-confrontational way with the provider. Be inquisitive, but not questioning the provider's decisions. Explain you understand how hard they work, and you want to ensure proper payment for all that hard work. Less than ideal documentation is a recipe for inaccurate coding and payment.