DLC Question

[City Builder]

Hi,
I was about to buy Patrician IV rise of a dynasty when Steam informed me that I already own it.

My question is that it's supposedly a stand alone DLC, however Patrician IV shows it to be about a 2.8GB download and the DLC only a 1.1GB download.

Do I need to have the Patrician IV Steam special edition installed to install the rise of a dynasty DLC?

I ask because if it's a stand alone product that contains all of the Pat IV Steam special edition and the DLC then why would it only be 1.1GB when the base Pat IV game is 2.8GB?

What is missing or has changed that reduces the base game from a 2.8GB download to only a 1.1GB download with the base game and it's DLC?

Thanks

[💀 Klq X Klly 💜]

Im not sure but it wont let you play rise of a dynasty without the steam special edition