Helpful advice: Do not try to change the complexity, re-use factor or adjustment effort before updating a use case. You will lose the adjustments you made. You will want to either update the use case first then adjust the complexity and re-use factor or at least write down what your adjustments were so you don’t lose them.
Yeah, I ran into that problem. I was figuring out the system and made an adjustment to the complexity and later went in to modify the use case and a confirmation message popped up. At least they warned me.