If you have an unpalatable Bill to put before parliament, it wouldn't be a bad idea to propose a Bill even more distasteful. That way you could offer concessions to any rebels. Those rebels would feel they had won the battle and vote in your favour. What those "would be" rebel MPs don't realise is that they have voted for a Bill that they would have turned down on face value.
How many Bills have we seen recently where there have been a supposedly large number of rebels, and how many of those votes has the government lost after "concessions"? I can't think of any. The most recent examples would be 42 Days and today's Planning Bill. Concessions were offered in both cases (and alleged bribery in the former) and I honestly believe that both these Bills would have been rejected if they were presented in their post concession form in the first place.
Did the government get exactly what they intended on 42 Days and the Planning Bill?