Ha ha ...... believe me, you won' have an attenuation of 96dB and be receiving DSL over fixed-line cables.
.
This is why it is paramount to know the
exact distances involved combined with the
exact make-up of the cable. Long D-side line lengths have often been made up of a hybrid of higher poundage cables, such as 0.63 Cu and 0.9 Cu, which would bring your attenuation right down to a, 'within range' integer.
Ezzer (an ex-BT engineer with a wealth of knowledge), along with other educated members of the forums had a mini-discussion here ...
http://forum.kitz.co.uk/index.php?topic=1448.0 .... about something similar. You will notice he had a line in-synch at 9.6Km (I think he said ?), but this was fed over mainly 0.63mm Cu cable.
My own personal experience has seen me attaining synch (ADSL) on an 86dB cable-run, albeit only at around the 0.3meg mark. Spent days wih another engineer, clearing umpteen battery contact faults in wet buried joints up a very big hill, in order to get a 'Line Test OK'. Knowing full well, that even when we had achieved this LTOK result, the circuit would struggle like hell to synch. But them's the rules, the ISP's require a LTOK and quite rightly so.