"Vantexan" related a situation much like this sometime ago.
Since minimum pay requires an employee to work all hours scheduled and OFFERED, if you are below 35 hours in your normal 5 day work week - and are offered work on your scheduled day off, and you refuse, I believe it constitutes an automatic waiver of minimums.
Take a look in PEOPLE, section that deals with pay, then requirements for minimum pay. I'd bet dollars to doughnuts that the key phrase "offered" is still in there.
PEOPLE is also changed according to the whim of Express without them notifying the employees of a change, so just because something is policy at one time, doesn't mean it is written in stone.
Actually if you are on either a 4 or 5 day schedule and don't get a full 35 hrs they can't make you work a day off to get at least 35. In my case mgr was forcing me to work less than 35 hrs and waiving my minimum. I volunteered to work Saturday to get more hrs and usually ended up with 36-38 hrs on 6 days. Went to the company about it after transferring. I felt all those weeks where I worked less than 35 on 5 days I should've been paid the difference. If I worked 32 hrs, should have been paid for 3 hrs. But company said the hours I worked on Saturday could be applied to my minimum so I only got reimbursed for 2 weeks I didn't work Saturday. Southern V.P. told me week was 7 days, not 5, and plenty of employees get their guarantee on more than 5 days. I've been all over the country with FedEx and never saw that once.