@msedaka 

I understand that you want to expand your TP-Link Deco BE85 3-pack system with additional BE63 units and are concerned whether this will reduce the performance of your original BE85 units, essentially making your whole system perform like the BE63/BE65 models. According to our knowledge base, while you can mix Deco models (including BE85 and BE63/BE65) within the same mesh network, the overall mesh performance may be influenced by the capabilities of the least powerful unit in the chain, especially if your devices connect through the BE63 units or if the backhaul between nodes involves the BE63. The BE85 has higher maximum Wi-Fi speeds and more advanced hardware than the BE63/BE65, so if traffic routes through a BE63, speeds and features will be limited to what the BE63 supports. However, your BE85 units will still retain their full capabilities when clients connect directly to them or when they are used as the main router. To maximize your mesh performance, it is best to connect high-demand devices to the BE85 units and, if possible, use wired backhaul between nodes. Adding BE63s will not 'downgrade' your BE85s, but the overall mesh experience in areas covered by BE63s will be limited to BE63 performance.