…..and this is completely false.
"Variant dumps", while they may feature numerous different variants to choose from, the amount of each book available are almost always very "limited" as specifically stated in the solicitations when Diamond has done those.
In other words, inventory from remaindered case packs.
Furthermore, "unreported international orders" account for 10% or less of what Diamond ships, which, if anything, can be used as a reasonable counter balance when estimating numbers, given the fact that, as you mentioned, not all orders will qualify for a variant, and that variants themselves are included in the Comichron sales reports.
-J.