Outcome overpayment decisions are relevant decisions and are appealable ( and the appeal can raise any relevant issue, so any determinations embodied in the outcome decision are up for grabs (R(H)3/04, CH/2931/2015)
There is strictly speaking no such thing as underlying entitlement. What Regulation 104 does is provide for sums that would have been determined to be payable in hindsight to be taken into account when calculating the amount of a recoverable overpayment
Note the word here is "determined" What is in the shorthand referred to as applying underlying entitlement is not a decision, but a determination necessary to revise the (previous) outcome overpayment decision.
The previous decision then ceases to exist and becomes the decision as revised. The decision as revised is of course appealable.
The appellant can effectively revisit the entitlement decisions on an appeal against the revised outcome overpayent decision
See also the thread http://new.hbinfo.org/forums/topics/revisiting-2012-decision
