You are right in the fact that on paper, you appear to be elligible for an age waiver, but it is all dependent on the agency component you are seeking the waiver with, and how bad they need your services. Once you get an age waiver from any DoD component, you are good for all of them for as long as you can meet the physical requirements or you get the time needed for retirement.
In order to get the waiver, you need to be "exceptionally" qualified and current/recent ATC experience is required. No commander is going to give a waiver in your case when there is a plethora of skilled, qualified, and current military controllers available after retiring or leaving active service, and are under the 36yo age limit, and in no need of a waiver, or very deserving of a waiver. I will say that if you do get 52 weeks of experience you will make yourself more competitive. However, if you don't have a waiver prior to your 56 birthday then since that is the mandatory retirement age for controllers, then no command component will give you an age waiver.
For example, my age waiver I got at 43 1/2 years of age, I have been DoD now almost 5 years, my mandatory retirement age is 56 unless I don't have the time to retire DoD, which I will not have until I am 63, so as long as I can pass the flight physical I can control until then in order to have my 20, and if I wanted to go for 30 I could do that too, but don't see myself going much past 63.
Good Luck!
JM