ES Upgrade/OBC Question..

Say I'm booked in a 4G for $900 and the current promotion has 4E with a free upgrade to 4G for $850..

Am I entitled to that $50 difference with ES?

I'm almost positive that I've been able to get this type of OBC in the past, but this time Carnival is saying that it's now allowed and never has been.

Am I losing my mind or are they wrong?

You have to match to same "everything".

So because another cabin category has a discount, unless you are booked in that exact cabin category, you cannot "claim" the other cabin category discount.

Your attempt is like trying to get a lower price on clementines when regular oranges are on sale.

I have gotten these types of upgrades/credits in the past. YMMV though

If there is an upgrade from the 4G to another class and the price is the same, you can get the upgrade. Last cruise I got an upgrade and OBC due to a price drop with free upgrades.