Not getting IX speed when uploading to http file server

My isp uses a mikrotik router . Our country has an IX which we use to transfer local data at high speed. Problem is when somebody tries to upload something I get the package speed( i.e downloading from steam/origin or browsing facebook) which is around 2.5 Mbps. Normally when I download from my friend or my friend downloads from me, we get the IX speed which is around 30~50 Mbps.

In short, Suppose User A and B are connected through a IX with 50 Mbps b/w. A downloads from B @ full IX speed.

B downloads from A @ full IX speed.

B uploads something to A @ normal speed of A.

Checked the traceroute. packets passes through the IX

What is IX and what is the question?