A loop with changing numbers in the question, that vary depending on the answer

Hi!

I want to create a task in which a person has to decide in a set of 7 questions. The decisions are simple questions, as to whether they would accept a certain monthly payment, that is given in the question. I want every decision to influence the next question (e.g. if someone doesn't accept a payment of certain amount, the next question shows a smaller one, if they did accept it, the next one shows a bigger amount).
For now I am doing it using piped text, so there is the question, and then this line appears to indicate the amount:  $e{ ( e://Field/installment + e://Field/bank_commision ) } as the amounts are embedded. The survey then multiplies the bank_commision accordingly.
Now, I can input all of the questions variations manually, but it would result in me manually inputting over 200 questions in this block.
I know that the looping feature is there, but I am just not quite sure how to use it in this case. Does anybody have any idea on how to utilise it here?