He does not ante counters to charge up.
1. During ante, Burman declares a number of Firepower he will gain at the end of the beat. Note that this number can be adjusted upward during successive ante steps, but not downward.
2. Upon Reveal, Burman applies the Power and Priority penalties associated with the amount from step 1 (the amount Charged) to his attack pair.
3. At the end of the beat, Burman gains the number of Counters he declared in step 1, to a maximum of 5 Counters held.
I can 100% confirm this.