In my experience, it is a rare Hohner that is accurately tuned as it comes from the factory. Tones fight each other because of the inaccuracies. Most sound ba.. which unnecessarily drives folks to more expensive instruments when a simple professional tuning would do and give you a very fine box in a simple Hohner...

I would wager simply correcting what is known as Hohner's "almost" tuning in a stock instrument..
will improve it immensely.

Did you take a decible meter to it before and after to confirm your observations.