Doesn't seem to be anything fundamentally wrong, but it seems a very high ping time for a fibre connection... even with interleave on mine is less than a third of yours. (See links in sig, though they're with IDNet, not BT.)
Or maybe I'm being over-optimistic about what BT Infinity connections can be like, anyone else care to comment?
Those stats are likely to mean a lot more to someone else than they do to me
But the simple answer to your question is- no. If the DLM thinks your line is good enough it will (in it's own good time) put you on to fastpath, and if it doesn't it won't.
Mine wags between interleaved and fastpath every few months for no reason I've ever been able to work out