"Canadian Sesame Street" edits?

[YellowYahooey]

I remember watching Canadian Sesame Street in the late 1970s and 1980, and after checking out Muppet Wiki, I realize that there may have been segments from the American broadcasts that were replaced by other American segments when aired on CBC in Canada.

For instance, there was an episode in Season 8 that was brought to you by the letters B and M and by the number 3, and I recall seeing "The Bee Bee and Barker Family Reunion" letter B segment on the Canadian broadcast - which wasn't listed on the Muppet Wiki outlines. I also recall seeing "X Marks the Spot" by Sherlock Hemlock replacing the Harvey Kneeslapper "X Marks the Spot" sketch in the Canadian broadcast of Episode 1193.

Why did such edits happen?