It appears this is a new design someone is trying. Are they JD blades, or an aftermarket brand?
My dad always told me never to make a lawnmower blade knife-sharp - just take out the dings.
But, brand - new blades from Snapper or JD (for my Deeres, anyway) are sharp enough to shave with - so I discarded what he always said, and dress them once a season to the knife edge they came with new. (maintaining the same angle)
But, if yours CAME dull, it is probably in the design, and I'd leave it (and dress it next year) that way. Unless you got a blade that someone forgot to sharpen. :wink:
Take a pic of them before using them, so you have a reference to how they are ground, and/or draw yourself a 'profile' pic.