On the Retirement Statements, "gross" actually just means "total/all/no adds or subtracts" - much like the SS documents that in box 5 have what you actually received, but the detail to the left begins with the amount that you are due to receive, but before other items of deduction.
The amount in box 1 "should be" the total pre-tax figure. I am not sure where you are seeing (or saw) the "pre-tax figure" of $5500 if it is not on your tax form.
