What have I bought?

Milan2020

I have paid for Bitdefender Antivirus for Mac for the reduced newcomers rate (£19.99) and it is showing in my Subscriptions.

Why am I being asked to buy the similarly named Bitdefender Antivirus for Mac in Offers at an additional and significant cost (£31.99)?

Whatever distinction there is was not explained in advance although, part way through the purchase process, there was suddenly a demand for an extra cost which I did not take.

Please help me understand for I am not impressed by this at all!