Help, my updated posts keep bubbling to the top of the Planet

I kept noticing that whenever I updated certain posts they would end up at the top of the Planet Plone RSS feed aggregator. I haven't dug too deeply into the issue, but it seems to be a mixture of the way the Planet is configured and the way default blog feeds are presented by Blogger. Thankfully, the default Blogger feed format can be easily changed.

Previously the feed I used for Planet Plone looked something like this:
http://pigeonflight.blogspot.com/feeds/posts/default/-/plone
Which resulted in a feed enclosed between feed tags like this:

     <feed xmlns='http://www.w3.org/2005/Atom'...

My new URL now looks like this:
http://pigeonflight.blogspot.com/feeds/posts/default/-/plone?alt=rss
The new approach (ie. appending ?alt=rss) resulted in a feed with an rss tag like this:

    <rss xmlns:atom="http://www.w3.org/2005/Atom"...

I did not delve into what other things get changed by using '?alt=rss', but the most important outcome is that the "Planet" (Planet Plone) is now safe from the occasional updates and revisions to my blog posts.