That's exactly what I am saying.

What benefits were changed from cash to benefits in kind at the same time?

Housing benefit didn't used to go to the tenant. It went to the landlord, it would show up in a higher deciles numbers. They've moved who gets paid the money.

The higher decile numbers wouldn't be affected by that change, it'd be income either way. The question is not who it was paid to though, it's whether the tenant was considered to be getting a cash benefit or a benefit in kind. In the context of disposable income it would have made perfect sense to take housing benefit paid directly to the landlord as a cash benefit to the tenant. Because the tenant chooses where that money is spent (even if limited in the sector, they still picked who to rent from, they were not assigned a government house).