I'm still puzzled by the same issue: I assumed 'concentration' must be the answer and I realised that 'ration' was an allowance - or possibly a meagre allowance - but I can't see how 'concent' fits in.
And, in a similar vein, I'm stuck on justification for the following:
5d: why should 'masse' mean 'stroke'?
21a: why should 'berg' mean 'order' (assuming that 'amo' is 'Roma' backwards without the R)?
44d: I'm guessing the answer is 'tumbril' as a form of transport, but I can't see how any of the rest of the clue works.
54a: I'd guess the answer is 'lustre' - but, since I can't justify any tiny bit of it, I'm probably wrong. In any case, what is the answer - and why??