Honestly, I doubt your method is doing anything different than a lineup where the trainee is also listed as the starter. It's possible your method works better, but I'd want to see more examples of games where it worked (and similar games where actually listing the starter didn't work).
this method has been no secret and it works. in fact, it doesn't even have to be how volkanegeu said. Let's say you train your PG.
PG: Blank - Trainee - Trainee
SG: SG1 - SG2 - SG2
SF: SF1 - SF2 - SF2
PF: PF1 - PF2 - PF 2
C: C1 - C2 - C2
So basically 9 man roster would work as well without messing up the minutes.