Totally agree. I have a breeding pair of Pearls.Scobina don't have a disc size of 18¨, not even close tbh. The biggest they (pretty much) get is ~14¨ for a female. And Pearls get bigger than 18¨, 22¨ easily for a female.
Male is around 18" disc and female 20". Both a good 2 foot including tail.