Greg, welcome. If you have an understanding of the technology involved you won't be concerned. First, you can't choose what impedance to run speakers at; this is determined by the internal construction of the speakers and can't be changed by the receiver. For example, your(and my)M22s vary between about 3 and 20 ohms at various frequencies and the M80s vary between about 4 and 14 ohms. Manufacturers generally put an average impedance rating on their speakers and the M22s are no more 3 ohm speakers than the M80s are 4 ohm. The so-called impedance setting on receivers is somewhat misleadingly labeled, as what it does in actuality is to reduce the voltage output to help prevent overheating during UL(Underwriters Laboratories)safety tests. The reduction in voltage capability results in a reduction in current and power(following Ohm's Law)and tests have shown that the use of the lower so-called "impedance" setting cuts maximum power capability roughly in half. The setting should never be changed, regardless of what impedance rating was given to the speaker, and should be left at the default of 8 ohms if the maximum capability of the amplifier is to be realized.
So, there's no reason to be concerned with the impedance rating of the VP150s, and whatever you decide about speakers, don't consider changing the receiver "impedance" setting.
