I think everybody's situation is so different you can't use any rule of xx% of your current expenses or income. Some people have the $300 toll charges and gas and new suits for work and all that, which will go away. I work from home and dress very, very casually, so I may actually drive more when I'm not tied to my desk during the day. Some will travel more. Some will move someplace a lot cheaper. Some know they may have to or want to continue helping kids and grandkids, while others will cut the cord. Health insurance will almost certainly go up until age 65 unless you get medical in your retirement plan, which happens less and less these days.
I think you've got a good start by tracking your current expenses. From there you ought to be able to do a decent job of estimating how those will change when you retire based on your situation.
You've already figured out that your tax situation will change, and that you no longer need to allocate for saving for retirement once your there.