I have changed my opinion...He does rightclick scan only or also executes the malware?
If rightclick only then dont know if rightclick scan uses cloud or not?
If rightclick scan doesn't uses cloud then this explains the difference in detection.
BD free and BD paid have same detection, but BD free detection of inactive malware on system is slower due to the way it works; user has to be signed-in to BD account all the time for signatures.
For those that BD free works well on their system, it is good antivirus... if all they want is AV and use Windows firewall...
For malware already installed on system, BD free is good but will leave registry and file remnants; in such a case user should also use Malwarebytes free and Hitman Pro. That combo does good for basic, general system malware clean-up.
Difficult clean-up need to use MT's Malware Removal forum... Twin Headed Eagle or Argus.