Region : Argentina

Model : TL-WPA281

Hardware Version :

Firmware Version :

ISP :

Currently have WPA 4220 kit. Base unit connected to BT HomeHub4 and WiFi unit on other side of house (Sky Box wired & WiFi for phone etc). Cloned to provide seamless WiFi connectivity as per instructions. Works perfectly. Now want to expand network to upstairs and garage as WiFi very poor in these areas and I also want to add game consoles via wired Ethernet. I know that you can add up to 16 units to this system but am unsure about if there is a definite base unit and a definite receiver unit.
Question 1 Can I use another WPA 4220 kit and use the "base" unit provided to pair with existing network, then repeat for WiFi unit? So I now will have 1 base unit and 3 receiver units.
Question 2 If yes to question 1, will I need to clone the new units so I don't have separate network id's.
I don't really want to buy a single WiFi unit as the kit is actually better value and I could use the extra power line for laptop.
Thanks in advance.