I takes me a minimum of 45 minutes to fly sparge the mash for a 10 gallon batch. I consistently get 90+ efficiency.
I gave up the 10% efficiency to save 30+ minutes. I was also worried about over-sparging. From the forum and reading I found that over 85% was not particularly a good thing.
On the teig side, I've only experienced this in quantity with multi-step mashes or when I perform a protein rest.