I think it depends on how much boob tissue ( I know that’s probably not the correct term) you have to start with.
I read online that the size they can offer is limited by the measurements of our current breast. Also if they let you choose high profiles ask for that as gives a bit more volume than the moderate ones 🙂 I was also unsure of sizes because of all the different results online, maybe see if you can have a further consultation to try them on again and see.
I’ve been offered 300cc same for both sides and I had asked for a full C cup. I’ve seen some girls with smaller implants get D and DD cup so it’s so confusing. I’d go with what the surgeon told you and get a second opinion from another surgeon if you must. But they measure you and know what best what is possible and what is likely to be the result based on your personal measurements. Hope this helps.