For what I can understand after trying to redo the template as it has some missing relations, your result it is correct.
Goal to save: 200
Actual Savings: 250
So the progress marks 100% when you meet the goal, meaning, when actual savings it is equal to goal to save, that is 100%.
But, when you exceed the goal it goes up and that is correct, because 200 is 100% and 250 is 125%, because you are exceeding the 100%. As actual savings is over the goal, then the result is correct.
You will have to rethink the structure as it is not clear what you are trying to do.
Progress bars "with limits" can work as you need, for example a list of tasks, when all of them are completed, that is 100% and the result will always meet that rule, you can't have tasks over 100%, because all of them create the 100%.
But if there are no limits and you just sum and sum and sum, then you can end up with 900% if you actual savings have that amount, there is no limit to go over the goal and that is the problem you are facing.