What is the ‘Agreement for Sale’ and is it binding on the ‘promoter’ and the ‘allottee’?

As per section 13(2) the appropriate Government is required to specify through Rules the ‘Agreement for Sale’ to be entered into between the promoter and the allottee. This Agreement is binding on the parties, however, internal flexibility could be provided in the said Agreement for Sale, for determination / insertion of other provisions as decided between the parties.