Mr. Blaze said: "But my question remains why was it left off the album?"
Probably to save it for their The Best of the Cowsills compilation, released mere months after this LP (and just in time for the Christmas shopping season!) Makes good marketing sense, anchoring their greatest hits with a track not on any other LP at that time.
I own this USA release and there is absolutely no difference in any way to this release. Appears to be yet another case of the USA release simply being sold in Canada, but should not be listed as a unique Canada release.
Again, this just looks like the USA release with no difference in sight. It may have been sold in Canada, but I see nothing to indicate this being a unique Canadian issue.