SCA works very well at GA speeds - at 90KIAS a 40 deg SCA works admirably, with a timing allowance of 1/3 of the time spent making the correction. Even if it didn't get the pilot exactly back on track, it would get him to a position where he would be able to reognise his pre-planned track.
But since I know who you mean, I'm hardly surprised. He doesn't think that 'point and power' works on the final approach in light a/c either. Which of course it does!
By the way, 'New Track Reference' means reference to a revised (or 'new') track - not that it's a new method of navigation!