All of these are examples are nothing like this ride at all.
This is my thinking of a hypothetical but possible situation.
You visit and ride just the adult coaster version, the ride then breaks down for the rest of the day.
are you saying you completely have the credit?
If so, let's say you return years later and they've removed the adult section completely and just left the junior section, are you still saying you have the credit?
If not then I'd say it's 2 credits.
If yes, that's fine. It would be really weird to me and no way I'd count it like that. But it's a valid opinion.
There's also the option of 1/2 credits that some people use on Mobius coasters, but no way I'm having .5 credits on my count