I have this behaviour:
When the plugin is deactivated, the markup shows correctly in GSDTT, I can see the image, time and calories in the snippet.
When I activate the wp-postRating, all this disappear, and in behalf I can see the star rating with related additional info.
I can't get them to work altogether.
It looks like activation breaks my markup. I use the [ratings] shortcode beneath the post content, below the first picture of the recipe (it is actually nested then into itemtype="http://schema.org/Recipe")
My website is http://www.cookingwithpeachy.com, not all recipes are marked up, posts from year 2014 yes.