According to Reddit user Diablix,
Try breeding your starter with a ditto with egg power 2 and you can sometimes get 4 eggs in 1 minute, but try breeding that same ditto with a hypno with egg power 2 active and you can potentially be waiting 4 minutes for an egg, followed by 2 eggs in the next 45 seconds (these are the results I got while testing immediately after reading your post)
This may not be the most reliable source so I can hide the answer if you don't find it satisfactory.
Source