I also had an experience like yours when I first started all grain. I hit 92% once. Over the last few years changing my process and adding/deleting brew rig components I'm back to 72-78 almost every time. That's pretty much the average anyway and it's less work that way for me too. Eventually you'll be able to dial in your process but for now make the said eff adjustments to compensate. Take mental or better written notes of any process changes and you'll be able to find what works best for you.
Fermentation may have been a greater discovery than fire."
-David Rains Wallace
My Brewing Apparatus