Need help understanding Mystical Egg Bonus

Definitely something I should understand by now but it's just so confusing to me.

How do Prophecy Eggs work? I had no boosts going and a full capacity farm and was earning a certain amount per second as displayed above my hold to hatch bar (i dont remember exactly how much). I claimed a Prophecy Egg, and my earnings per second remained exactly the same. Isn't the Prophecy Egg supposed to raise the value of my eggs? how does it work? for reference i had like 500 trillion Soul Eggs, 7 Eggs of Truth, and 17 Prophecy Egg before gaining the 18th Prophecy Egg