Inserting Hardware via i/o plugin

I am on Protools 12.4. A Macbook Pro with OS 10.10. My interface is a UAD Apollo Twin Duo which has two stereo out and one stereo in. 1/2 out for monitors and 3/4 out for headphone/output etc. I am inserting the i/o plugin on my master bus to use my API 2500 as a plugin. I am only getting feed back this way. Everything plays through the API when I send it via output 3/4 on every track including the master bus. I observed that the i/o plugin in Protools is not like the one in Logic Pro which is straight forward. Select 3/4 out and 1/2 in and that's it for Logic Pro. Am I doing something wrong? I want to do more mixing via the API in Protools which has some features that i like.:eek::eek::eek::D:D:D

Inserting Hardware via i/o plugin