Avery strange set of figures ...
0.5 dB - even next to the exchange would normally get 2dB or more. Then with the noise margins - I would expect to see the UP figure being way more than 7dB and similarly with the down figures unless you are in a really "electronically" noisy area.
Can you check them again ...
Do you know how far you are from the exchange - straight line and by road?
M H C
taurus excreta cerebrum vincit