That would be great for me too - except for the Transport category (& any similar categories that are added when the categories are reviewed) because this is a fixed monthly cost for me.
As I mentioned here -
I adjust my targets each month, based on how much I spent between payday & the start of the new month (or if I pay for expenses, holidays & other costs spread over several months). So the option to simply adjust all of my targets by a single % at once would save me time.