Due Date only calculated for first card in list

[nbsmokee]

First of all: I love the idea behind this Power-Up, since it does exactly what I was looking for, or at least it should.
The calculation of the due date works fine, but unfortunately only for the first card in the list that has a time estimation set. All cards below the first one are not updated. If this could be fixed, I would be very happy.
🍻