Insurance companies have changed a lot about the process. My doc suggested it, then scheduled it spot wouldn't interfere with his vacation time. It all worked out perfectly. But 14 years later, there are a lot more hoops to jump through and people to handle you. It sure wasn't necessary for me, but I think they're trying to see if people can follow rules before approving the surgery. They're really just covering their asses.
I'd work out a schedule with the doc and put it in the chart before going home. Theoretically, every other tech would consult that first and fit their tests around it. The surgeons availability is more important than all the others. They need to follow his/ her schedule.
My wait time was nine days and I wasn't required to lose weight. Worked out fine for me, 75 pounds down in 90 days, then stalls and loss for months, until I dropped 115 pounds. At some point it felt like my body just took over and I obeyed.
I think asking your doc for a letter to expedite things is worth a try. You're having the surgery. You're going to lose weight. Why make the pre-op so hard. Seems very cruel.