They could be parodies of J Mann cuts; but they sure sound similar musically
( which is an awful thing to say if they were indeed J Mann’s work, but you know what I
mean)
It seems the jingles J Mann is doing now are still top notch– His singers may vary a bit is my guess too.
Have a look at this page- to the 8th video down; J Mann singers session clip-
Ahh the things I find looking for things I didn’t know about 
http://www.randycrenshaw.com/video/TELEVISION%20SOUNDTRACK%20VOCALS.html
This is just an aside – as the jingles & imaging got longer everyone sits stonefaced waiting for them to end
http://www.youtube.com/watch?v=ws58s9wzYsA