Dave
I would go along with that; the tendency to repeat exactly as it was heard from the radio was very common with the singers we met.
It's the old story of Walter Scott collecting ballads from James Hogg's mother, who told him, "Now you've written them down you've killed them".
Walter on the other hand learned nearly all his songs from family and neighbours and had picked up his singing style from his uncle, so he sang everything in his uncle's style (we think!)
Jim Carroll