The reasoning for the majority of the mixing is exactly the same as the sabino Arabs: The AQHA didn't like the excessive white, so they were automatically sent to the APHA, who, at the time, allowed it. So there you now have loud colored Quarter Horses registered as Paints and it took a while before the APHA said screw that and the AQHA was forced to keep them. However, the majority of the owners of those horses did not go back and re-register their crop outs as AQHA and left them as Paints.
Then you get to horses like the OP's, who come from APHA lines, but did not inherit the white genes or just doesn't express them loud enough (and it's the APHA..they only care about how the horse looks, not it's actual genetic makeup). What if that horse is from crop out AQHA horses? Does that make it AQHA because it doesn't have a pattern? No. Only if the parents were double registered. Or like the OP's and it's mixed with AQHA and actual APHA tobianos. Then you are still left with a solid APHA horse that is separated into its own section.
Neither of the breeds are pure, so I suggest if you'd like a pure breed, you stick with your Arabs.
Last edited by Poseidon; 07-21-2012 at 03:31 PM.