Thansk for your replies really appriciate. However i think i didnt post my question in the right context. I understand the loadbalacing mechanism per AE from a single device point of view. My question was more around the return traffic. As i said on the switch i could see by default sometimes the north direction of the flow will go via member interface 1 and the return traffic for that same flow will be via member interface 2. Sometimes it chooses the excact same physcial member for both directions of the flow.
On the MX on the other hand we did these same test, both directions of the flow kept on the same physical member, after the several test resets we can see the flow even moved to the secondary member and also the retun traffic moved to the second member. So during these test we could observe asymetric traffic whereas with the MX it kept on being symetrical. This is actaully what i need to know. I will be putting a transparent device on the links and need to know what go out on member must return on the same member interface.
Hope this sense regarding the symatric