"An aircraft can only fit into one approach category. If it is necessary to manoeuver at speeds in excess of the upper limit of the speed range for each category, the minimum for the next higher approach category should be used"
Agree.only one certified approach category but minima of a higher may be used due to non normal higher SPEED (which indirectly comes from a higher VREF.)
So a Cat C aircraft would become Cat D, and so on.
No you dont become cAt D,you remain cat C but you use cat D minima.
Your catc is FIIIiiIiIiIiXxxxxxxED by operator/regulator!
The radius of protection you showed is for TERPS,PaNOPs are wider.