Here's the way AOV works where I come from. I'll use the State Fair as an example but some other fairs work this way as well. The Fair entry book lists certain varieties eg: Barred Plymouth Rock, Partridge Plymouth Rock, White Plymouth Rock Buff Plymouth Rock & AOV Plymouth Rock. AOV would be Columbian, Blue or Silver Pencilled, the remaining named varieties. It would not include Caloco Plymouth Rocks or any other experimental, non-standard variety. In other words the AOV {any other variety] still needs to be an established variety.
In non-fair shows or fairs that don't list specific varieties in their catalog it's different. I will speak for the two APA/ABA shows that I am secretary for. We do not take AOV entries. Your Calico Cochin would be entered as a Calico Cochin & would be judged against any other Calico Cochins present. Since Calico isn't a recognized Cochin variety the highest award it could receive would be Best of Variety, that variety being Calico Cochin.
Writing AOV or anything else on your coop tag would be a bad idea as the only person allowed to write on a coop tag is the judge. If I were to come on a coop tag where the owner of the bird had written anything I would disqualify that bird. Also if the coop tag doesn't show what's actually in the class most judges will write "wrong class" on the card & not judge the bird.