I targeted 5.5 gallons post boil to account for dry hop absorption. I am pretty close to 5.5 gallons.
Besides the low OG, everything else went well on brew day.
One thing I am questioning now is MoreBeer's crush. As a mash-in-a-bagger, I always request double crush. MoreBeer said "we don't double crush but have fixed/adjusted our milling." Apparently customers attributed low efficiency to poor crush. My customer service rep told me a lot of customers were dissatisfied with their crush, enough so that they changed their process.
This is my lowest efficiency yet and the first time ordering from MoreBeer.
Googling "more beer crush" yields similar experiences.