Hi,
4 weeks is not at all unusual, I'm afraid. It's worth sending the DWP a copy of the short decision notice from the tribunal - they may not have even had a copy yet.
A tribunal can only look at how things were at the date of the decision, so it would not be lawful for them to make an award from the date of the appeal. If this is what they have done it sounds like an accidental error and you would need to contact the clerk to the tribunal about it.
Good luck,
Steve
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