If Zen are able to disable the operation of the DLM for your line, assuming your target SNRM is set to 6 dB and that the SNRM does not swing wildly between the hours of daylight & darkness, then you could tweak the target SNRM downwards by ~2 dB.
An approximate 2 dB reduction in target SNRM should give you about another 1000 kbps in DS sync speed.
