Every deal is different. Pricing is not fixed. If borrower A is in a Detached Condo with a 780 FICO score in the 92618 zip, and Borrower B is the same in the 90003 zip (LA County) there will be minute changes in price. Loan to value impacts things as well. One might be at 2.99 at 80% LTV, but 2.875% with a 59% LTV.
My advice here is to find the right rate with a lender you can move money over to for a better discounted rate. 2.99 at Quicken is not the same 2.99% rate at Citibank if you have $100k-$250k to move. Also, ask what the cost is at 2.875%. If 2.99 is "fee free" but 2.875% is $2,500, perhaps it makes sense to pay the cost. If your breakeven point is between 2-3 years between no cost and a rate with costs, pay the fees.
My.02c