So I went to the Costco site. I am an executive member. Mutual of Omaha had the same terms as Rocket Mortgage, but the lender costs were capped at $250 plus appraisal fee...good, huh?
And then this:
* Estimated Total Fees is a combination of lender fees including application, commitment and processing fees, as well as other third party fees such as appraisal, flood certification, credit report, etc. Due to the complexity of state by state charges, this does not include title, escrow, transfer tax, or recording fees. Lender fees are not to exceed $250 per transaction for Costco Executive Members, and $550 for Gold Star and Business Members
Payment estimates shown do not include taxes or insurance and will be higher once included.
The fees represented are not all inclusive – additional closing fees may be incurred upon approval of your loan application. A full quote of all fees and charges specific to your situation will be provided by the lender in the form of the Loan Estimate.
***
So it's not at all clear.