Extreme black cannot be achieved by breeding normal black to be darker. You can get a better black mouse that way, but extreme black is way beyond that...it's hard to describe...no trace of pink even in the 'pink' of the eye or the tip of a toe. Thje ones I had must have been ae ae because they were weird looking; huge long tails and big ears with a relatively tiny body and head. I got the biggest mouse I ever bred from a pairing with the extreme black buck that yielded Monster who was 12 1/2 inches from nose to tail tip. the female never conceived, so I let the gene lapse, but it's probably still hiding in the mix somewhere. The overly dark chocolates are probable evidence of that.
People offering judgment on pet mousies beyond responding to the substance of the inquiry or of the purpose of the post is pointless, as this is not a judging area at a show. Become a judge and do it at shows, and no doubt you all will be very well received. some of us just love mousies, even if their coats are 'poor', just because, hey, they're mousies, and we love 'em.