So, let's take this a step further. What about Blue wheatens? The SOP doesn't refer back to the Columbian SOP - it just says "Breast - blue, preferably laced with dark blue." You're not going to get dark blue lacing using those pattern genes, right? You'll get black lacing, which is not in the standard. In this case, I would think the natural "edging" of the blue dilute gene would be sufficient.
I see what you're saying about the crossing varieties, but I would still debate whether it was necessary to bring in black to avoid the over-dilution of the blue from time to time. I've read different opinions on this, but have also seen long time Andalusian breeders that recommend the same. Granted, if the lacing is from the combination of pattern genes, bringing black back in won't help lacing, but it definitely would add some of those melanizers back in to darken the blue again.
If anyone is interested:
@GaryDean26 once posted he had (I believe an out-of-print or old) handbook on breeding Blue Andalusians and he used the tips in the book toward breeding his Blue Bredas for perfecting. If he would be kind to give the title of the handbook it might be found on Abe's or other bookfinder websites for purchasing out-of-print copies.