F451 - as you well know, it is not strictly true for you to keep claiming that "rents exceed the allocation from government", or however you try to describe things to make it seem as if social housing is not subsidised by the taxpayer.
The HRA system is described as follows in the DCLG descriptive document relating to HRA reform:
"The HRA is a “ring-fenced” account within the General Fund; this ensures that rent levels cannot be subsidised by increases in Council Tax and that rents cannot be increased in order to keep Council Tax levels down."
"Assessments of authorities’ deficits or surpluses are notional – this means that they are based upon assumptions made by the Government."
So, if there is a calculation resulting in either a positive or negative subsidy, it merely relates to how closely the Council's actual expenses have matched the estimated values that were used to set the HRA for that Authority.
The explanation continues:
"Housing Element surpluses are transferred to CLG where they are pooled and paid to deficit authorities: This keeps resources within the housing budget where previously they would have been lost to the individual authorities’ general funds."
"To ensure that authorities which are able to generate surplus rental income, even though incurring management and maintenance etc expenditure comparable with other authorities, make a contribution towards meeting the costs incurred by authorities which cannot generate sufficient rent income to meet such costs."
In other words, excess rental income from Authorities who have to pay "negative subsidy" to the CLG are not financing the Treasury, they are helping to support other Authorities who are unable to balance their own social housing accounts, perhaps because they have a large historical stock of older and more costly properties.