All you needed to do is copy the number that is written

This is true, but in the case of the 4000 odd CL packs I have bought in batches, this is not how the UI has worked.

I've probsbly made at least 15 CL batch purchases, and so was completely unprepared for this new, regressive approach.

If you've got the vouchers, I don't see why you wouldn't want those bonus packs. And so inkeeping with the UI CURRENTLY IN PLACE FOR CL PACKS, that box should really have been autofilled.