Conflicting information about pre-op diet length

I wrote the following email to the nutritionist:

"Hi Marie!

My gastric sleeve surgery is scheduled with Dr. Lopez on 11/3. The instructions say he wants me on the pre-op diet for 5-14 days but the consent form says I cannot be heavier or lighter than 4 BMI points. That averages out to 20 lbs either way for me. Can you recommend how long I should do the pre-op diet? I normally carry about 8 lbs of Water weight and lose it pretty quickly when I start dieting. I am 5'7 and currently weigh 260. I recently had a ton of blood work done by my doctor and he said everything was within range except for my Vitamin D."

Her response:

"Hello Kristen,

My name is Marie and I am the nutritionist for specialized bariatrics. I received your contact information from your patient coordinator. I wanted to introduce myself and to let you know nutrition support is provided for you through me to guide you with your weight loss program and your nutritional needs. Should you have any questions or concerns regarding your food and nutrition, you can contact me directly via email.

Let me know how I can assist you with your weight loss journey. After looking at your chart and your history, I would advise to start on your pre op diet ASAP so that you can loose some weight as well as getting yourself prepared for post op recovery as well.

Please start with a shake in the morning and lunch, and sensible salad plus 6-8 oz of Protein at night. Let me know if you have any additional question.

Marie"

Am I the only one who thinks she is crazy for telling me I need to do the diet starting now until surgery? That's over 6 weeks. I don't want to get to Mexico and not be able to have the surgery because I lost too much weight. I've already paid for the surgery and I'm getting it done. If my blood work did not show any fatty liver then why would I need to do the diet for over 6 weeks? I'm thinking maybe I should just do it for the 5 days then 3 days of Clear liquids like my instructions say. I've never had to worry about losing too much weight...what a weird issue to have!