Does Ashton recommend 5-10% every two weeks or per month?

As far as I am aware Dr. Ashton's example slow taper schedules are not percent-based. The ones I'm seeing show a linear tapering schedule of 2-5mg/1-2 weeks with an attenuated ending of 1mg/1-2 weeks at doses below 10-20mg/day of diazepam, depending on the schedule.

The Benzo Warrior website claims...

Her protocol recommends making small, frequent cuts, tapering at a rate of no more than five to ten percent every two to four weeks, along with a switching to an equivalent dose of Valium to the benzodiazepine you are currently taking.

https://www.benzowarrior.com/tapering-methods

Maybe someone else can enlighten me, but I cannot find a single reference in Dr. Ashton's book where she mentions this 5-10% limit, or even percent-based reduction schedules. I thought it'd be in there, but I couldn't find it.

From the looks of your signature WPWP, you're already well into a Ashton-esque taper. I think you probably know now at what rate your body can handle tapering, and I suggest sticking to whatever rate keeps you functional. Dr. Ashton doesn't know you as well as you do. 

As per Ashton:

The precise rate of withdrawal is an individual matter. It depends on many factors including the dose and type of benzodiazepine used, duration of use, personality, lifestyle, previous experience, specific vulnerabilities, and the (perhaps genetically determined) speed of your recovery systems. Usually the best judge is you, yourself; you must be in control and must proceed at the pace that is comfortable for you. You may need to resist attempts from outsiders (clinics, doctors) to persuade you into a rapid withdrawal. The classic six weeks withdrawal period adopted by many clinics and doctors is much too fast for many long-term users. Actually, the rate of withdrawal, as long as it is slow enough, is not critical. Whether it takes 6 months, 12 months or 18 months is of little significance if you have taken benzodiazepines for a matter of years.

Another key phrase from the Ashton manual:

However, it is important in withdrawal always to go forwards. If you reach a difficult point, you can stop there for a few weeks if necessary, but you should try to avoid going backwards and increasing your dosage again.