Alex, Stuart, thanks for detailed answer.
I'm thinking about a further workaroud: Setup Material A.1 as TSM and Setup material A as TSM. If material A is manufactured (type is still manufacured/purchased), a custom hook assignes remaining time of material A.1 to material A. If materiall B consumes material A the Check-TSM-Hook can work as designed than.
Do you think that should work properly?
Regards, Anke