Yeah -- this is pretty ugly admittedly. Maybe control directive is ok, as long as you can set it mid function?
ADA uses for this purpose PRAGMA keyword - it is used for everything in ADA - cycle iteration optimization, ...the scope can be statement, block, procedure.
Pragma is used for changing (enforcing) behave. There are pragmas ada_05, ada_2012, ..
so something like
BEGIN
PRAGMA uncached_plans;
SELECT ...
..
END;
But it should be verified by some PL/SQL or Ada experts