Edea skate size??

Hi! Since I cant get fitted by a professional where I am, I measured my feet using the paper trace method i found on the Edea website. I got my longer foot to be 245mm and my shorter 240mm. So my edea boot size is 245 right? But I heard you have to add 10mm to your foot length for edea for growth room (i dont think my feet will grow anymore tbh) and you can go to size 250 for an extra half-size. I dont know if its the same with artistic roller skating? Is this normal? My street shoe size is 6. And the rental size 6 roller skates fit me well. I dont know what size i need to choose. I asked on another reddit group but im still a bit confused so any help would be appreciated. 😁😅