Blowing Strength

As a general practice should one blow with less strength on the higher holes?
All my harmonicas, the inexpensive and the higher end ones, seem to have very unpleasant overtones around holes 6 and 7.

I am not an expert, but I do find the top holes harder to play. I don’t think you need to blow any harder to make them sound, or as I am often told, you can hear me blowing around it! I sometimes find tilting the angle I’m blowing in the harmonica can help to make the sound clearer, especially on those high note holes on the right.

Hope that helps, and perhaps a more experienced player can chip in here?