The tribunal can only look at your situation as it was up to the time of the decision you are appealing against. If your situation has changed between the decision and the tribunal hearing, it cannot take that into account. However, the tribunal can take into account a change that occurred before the decision was made, but SSS were not aware of the change.
SS(S)A, S.49

If you are appealing against an outright refusal of your claim, your circumstances change while your appeal is pending and you think it is now clearer that you qualify for the benefit concerned, you should make a fresh claim.

If you are already getting the benefit (but, for example, not at the rate you want), let SSS know that your circumstances have changed. They can make a new decision, without you needing to claim. If you are not happy with this decision, you can ask for a further redetermination (see 2 above ), and, if this is not successful, appeal again.