Tony, spot on! Reaper did the magic!
I am surprised how well it came out.

When I was trying to fool around with file, it showed fluctuated tempo in Audio Snap...
Not sure how Reaper did it. Was it only BMP fix or it used a more advanced algorithm, like moved transient markers to make it consistent with bars?

Will sit some more with Cakewalk tonight. There must be a similar way if it is only tempo.
Good stuff to learn either way for future adventures smile