I've had direct experience of this problem. When 8.33 channels were introduced, for upper airspace in Europe, I was flying Boeing 747s. The radio tuning "Gables" heads were swapped with almost identical units that allowed the extra digit to be selected on the concentric switch which had grown from 2 to 3 levels.
Heading back over the Med early one morning Malta gave me a new channel to call Marseille but even though there were two of us looking at the "frequency" I still managed to miss-select it by one click.
The result was neither of us could here each other clearly. He kept saying "ooiscallin?" and I couldn't make proper contact as the garballing was severe.
Luckily P2 was more awake and quickly clicked over one more notch and we were able to hear ATC clearly. Thus getting both air and ground stations to "match" their frequencies is going to be the new game come Jan 1st.