Not a plausible one, but it is theoretically possible.
The claimant has to be in receipt of tapered Savings Credit: i.e. income above his/her GC amount, but no more than about £37 higher (single claimant). The claimant needs to have a change of income that reduces SC but is neutral in HB. The one we thought of is a small war disability pension where the council disregards the full whack. Receipt of adult matrimonial maintenance of less than £15 a week would be another.
The combined effect of such a change would be an increase in the SC taper, leading to reduced SC and new AIF, but the LA would modify the AIF to remove the new income stream so the only change for HB would be a drop in SC and, hey presto, HB goes up.
I suppose the Rergs have to cater for every possible permutation of one going up and the other going down, both up or both down, just in case it ever happens.
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