Hi there, I know a thing or 2 about service charges and in case 1, it would be a yes, the charge can be retrospectively reduced and the housing provider would need to take the necessary action to amend the charge over the period, which could involve a refund to HB.
In case 2 I would take a more pragmatic approach and suggest that in these instances it is more efficient to agree a credit to be carried forward to offset the ongoing costs as it simply saves on admin, i.e. to refund a service charge amiunt to HB someone has to advise of the new covering periods then HB have to reassess the amount due and then an overpayment needs to be recovered, if you think of this in terms of time taken to acheive the goal unless the amount is substantial the admin out weighs the benefit (NB if a tenant moves out who pays their own costs prior to recieving the full benefit of the overcharge being repaid via a carried forward credit then a refund should be given). If totally eccessive then a one off refund would be due.
In relation to the general theme, I have experience of working with many housing providers helping them improve their service charge procedures and recover more costs. In my experience, overall housing associations are losing money in the provision of service chargeable costs. There are always cases that highlight poor administration and over charges do occur, however, in general I truly believe housing associations are not recovering / charging the full cost of service provision.
I think this area has had more attention in recent times as housing providers are starting to put more work in to correcting this situation which obviously does create a reaction.
Management fees / admin fee - up to 15% is permissable, some providers opt to charge a lower rate, this is for managing the charge, i.ee arranging the contracts, doing the accounts, paying staff to work on service charges etc.
If you are interested in what your rent is for, I would point you in the direction of the Target Rent regime, which in my mind seperated rents from service charges and defined a social rent, if you are interested Ithis was first published in the governement green paper a decent home for all.
If you have queries on how best to challenge charges where you beleive they have been inflated beyond "reasonable" / "actual costs" pleae provide some detail and I will happily advise how best to query l challenge such costs.