Why no “Break in” period?

Not sure about  power  conditioners  but when I purchased speakers from a company that does online sales when I asked about break in the president of the company told me the only break in would be me getting used to the speakers. I should give it a month or two before I made a final decision.

Measured with an accu-tuner they would measure different. 

There is also this little part of the story that seems to be skimmed over.

In the end we invariably find a measurement that matches what the ear hears and it becomes very obvious to everybody.

So they don't  stop with well some think they hear something and some don't  they investigate what's  going  on.