Growth and Infrastructure Bill

I understand why the Government are saying that the issues should be separated; whether I accept that logic is another matter. However, in relation to having one cut-off point of April 2010 because agreements entered into after that would have recognised the current market conditions, why does that issue not run for both scenarios—whether it relates to affordable housing or other components of Section 106 agreements? Why is it 2010 for one but an unlimited starting point for affordable housing?