At the end of the day there's no official explanation for where advanced CoO begins, so a good parameter is probably, out of convenience, affirming that something is advanced when particularly proficient compared to the first basic CoO we were introduced to. For example FS looks to respond to that parameter, and BoAT also seems particularly proficient, but more like an addition, a variant. Maybe if we combined the two, basic + BoAT we could label it as an advanced possessing of CoO.