Steve that's right thanks for pointing that out, i rarely see fleet or high usage vehicles so that would be another reason.
I am not an advocate of additives but I'm not against them either if there is a reason.
Case in point, i have one customer that does 3K OCI with Mobil 1, the engine is spotless and quiet but yet they insisted on cleaning it'
Apparently a friend of theirs was claiming the engine was running like new when i ran Kreen through it for 1K.
They were disappointed when it did nothing for them.
I hope no one takes this as i am trying to persuade or dissuade the use of additives, I'm only trying to clarify their intended use.