He probably would have ordered all 3 anyway but if you were very adamant on the 500 maybe not, most people have this turmoil of not being 100% certain about their size choice and start to panic about their choice the closer they get to surgery day that’s why they order multiple sizes, fingers crossed the 550 is there for you, maybe give your PC a call first thing mon morning if your admission is not till 3pm, just so your not stressing about it all day, good luck and hope you have a smooth recovery x