jmp242,
The SMART status check is basically a "Do you support SMART and is it enabled" test. The SMART short and extended tests are drive self tests invoked by PC-Doctor.
If any of the SMART tests are failing, I would backup the data and replace the drive. Even though data may be reliably read and written by the normal PC-Doctor tests does not mean the system is not doing retries or having issues. Failing SMART tests is the drive itself telling you it is having problems.
-Fred