The Archmage Mythic path has an ability called Crafting Mastery. The wording says
Crafting Mastery (Ex): You can craft any magic item as if you had the necessary item creation feats. If you actually have the item creation feat needed for a magic item you're crafting, whenever you attempt a skill check to create that item, roll twice and use the higher result, and you make twice as much progress on the item for any time spent. This ability does not reduce the item's cost or any other requirements.
Am I correct in assuming the bolded section also only applies if you also have the item creation feat? How would this effect something like cooperative crafting with your familiar if you had the valet familiar archetype or a non-mythic helper? It would likely never happen but for the sake of rounded question what if the helper also had this ability and was mythic?