Doesn't it depend on whether you have Time Assignability (TASS) on your line or not?
If you have TASS hours on your line (for whatever reason) you will only get overtime for the hours worked over the CAP..if OTOH you are TASS free (e.g; bank hours used to "get" you to CAP) then all overtime is payable...
In my defence I'd add I think only a handful of people claim to understand JSS, I reckon in reality maybe one person might have a clue..and I'm not of of them...
TBH looking at some junior (Longhaul) lines recently I'm not sure WTH there would be any scope or space for overtime.