[mothered]

Perhaps it is impossible to predict this?

If you order both Items from the same Amazon domain, It's fine - It will be deducted from their Inventory, regardless of where they decide to ship the goods.

I will still try DNA, but almost everything I have received from amazon, came by DPD with OTP

The OTP Is the Issue when hitting Amazon.

In such a case, another method must be used.

Just to clarify one small thing, when I receive the two items, 1 in each different address, I put the "wrong" item inside the "right" package, correct?

That Is correct, but don't mention anything about the packaging - only say you've received a wrong Item to what was originally ordered.