Hi Willem,

I'm not sure I understand your question and I want to give you a proper answer, so I am going to assume your question is: shouldn't you move from F7 to F rather than C7 to F?

More often than not a chord progression follows the generally accepted rules of harmony. There are always exceptions of course. A popular chord progression (sequence)is C to F to G7 and back to C, or 1 to 4 to 5 to 1. In the case of the Key of F, the same 1-4-5-1 progression would be F to Bb to C7 and back to F.

Ted's song moves from the key of F to the key of Eb. He wants to return to the key of F when leaving the key of Eb. The smoothest and simplest way to do that is to move to the dominant note of the new key, in this case from Eb to C7 (the dominant of F), then to F. The melody note or notes would necessarily be those notes within the chord being played. The notes Bb and G are common to Eb and C7 so you could sustain a Bb note or G note while playing the two chords (Eb and C7) and that would give a smooth transition into the new key of F.

Hope this helps.

Goeden Middag Vriend,

Chuck