the main reasons are the same as mentioned above.
try asking for a pair change if its a multi wire or changing ports in the main exchange.
one thing i noticed is that you are on 8 mbps plan but the rate set for you is 7991 kbps down and 491 kbps up (which is very low for the plan subscribed and due to low rate set u get high snr value for up) , usually the down is set double than that of the subscribed plan.
For eg. mine is 2 mbps 945 combo plan and the rate set for me is 4096kbps down and 1022 kbps up, by this i get speeds around 3.5 mbps and uploads around 1 mbps