Recently the IDA (Initiative demokratische Arbeitszeitrechnung) did an interview with the RAV (Republikanischer Anwältinnen- und Anwälteverein) on their model of labor time calculation. This interview has been published in the “Utopia” issue of the “InfoBrief” publication of the RAV. The interview, which is in german, can be found here.
The RAV is a political organization of lawyers which are working together with social movements on issues of democracy and human rights. You can find their website here