I've just had a council come up with something I've not come across before on overlapping rents

The relvant regulation is reg 7(6)(d) which says that someone can be treated as occupying two dwellings

"in the case where a person has moved into a new dwelling occupied as the home.......... for a period not exceeding 4 benefit weeks if he could not reasonably have a avoided liability on the two dwellings."

A benefit week runs from Monday to Sunday. If a claimant manages to get an offer and move on, say Wednesday 14th November, and gives four weeks notice on that date then 4 weeks expires on Wed 12th December, but I've now got a council saying that that period is 5 benefit weeks and so payment on the old home must stop on Sunday 9th December.

I've never seen this argued before, and I'm sure that wasn't the policy intention, but it is a difficult argument to refute. Any comments?

Housing benefit weeks start on Mondays and end on Sundays, and they can't apparently do part weeks, which probably explains it.

That is, for a given value of "explains", as in "as far as housing benefit law is concerned but not as far as real life".

It's an interesting point because actually we can do part weeks now (and should be). But it appears that the wording of 7(6)(d) does not quite reflect this position. I think if I was making a decision on this case I would looking at the actual period where there was dual liability, which in your example is 4 weeks, and I would determine that this length of time does not exceed 4 benefit weeks and so it's OK. It's only 5 benefit weeks if you count the whole weeks during which dual liability starts and ends. I appreciate that this interpretation of mine might be dubious because the regs do say "benefit weeks" specifically whereas I am effectively saying "any period of 4 weeks".

It seems to me that the LA in question (and it will be hugely embarrassing if it's mine!) is counting periods of time when there isn't dual liability, which don't seem right to me, but granted, the use of the term "benefit weeks" is not helpful.