I agree with the last few folks here talking about your lautering rate. The main reason for slowing the flow dramatically is that you don't want to compact your grain bed. This creates channeling, where the water flows through parts of your mash instead of it flowing around each grain, allowing...
I've gone from 5 gallons at a time to 155 gallons (not a typo) at a time. When you scale up, you're going to notice that you'll have to adjust something somewhere, for me it's dark malts.