New To This23

tl:dr at bottom,

I could use some advice. I went to see my dietician today (not a bariatric surgery dietician, I can explain why I am seeing her if you want to know). She knows I am going to have weight loss surgery as long as I hit the goal weight my insurance told me I need to be at. I have to be at the goal weight by June 24, 2023, in order for my insurance to pay for my surgery.

I had a weigh in the doctor's office a couple of days ago and weighed 301, my scale at home said 302. However, on the same day, the scale at a friend's house said 313. 

I knew I had this Dietician appointment two days later and I knew she would weigh me. I continued to weigh myself at home (after getting new batteries) and I was at 302 then 299 and today at home I weighed 303, right before my appointment, when I got to her office I was weighed and it said 313.

I am concerned about what to believe since the doctor's office and my scale show similar numbers. I also bought a new scale today and it said 313. 

The Dietician told me I needed to eat more protein, which honestly I struggle with. she said I needed 150 grams!!  I said are you kidding? that seems like a lot.  She used my weight to come up with this number. 

Should I really be trying to eat enough protein for a 300-lb person or should I be eating protein for a goal-weight person (mine is 170)?   

also, my clothing is loose like I lost the 20 lbs mine and the doctor's scale shows, and not 10 lbs like everyone else's scale shows. Also, I have always naturally been more muscular even when I was 120 lbs and did not eat any protein aside from what is in plants. 

tl:dr- should I be eating enough protein to support a 300lb person or should I be eating protein for a "normal" sized person? AND should I trust the Doctors scale more so than the Dietician's scale?