They 'were' a joint venture between the two manufacturers about 4-5 years ago ... and if I'm not mistaken, was a one time deal.
They are discontinued, and are no longer being made. Being made by both maufacturers, either name can be used to promote them. Since Drew Estates has a cult following at this site, it was good marketing sense to use their name. Look how much higher the bids have gone since they switched from using Perdomo ...