需要更新数组中的值，但保留原始值以再次更新它

I want to update a recipe to change the amount of each ingredient. Everything works fine when I put in the first value but after that, it updates against the updated values not the original values. I tried setting up a 2nd array to hold the original values and then exchange them but it didn't work. Here is a live version of script I want to update a recipe to change the amount