We can't show our working hours as Flarum is an open source project. We invest time next to all our other obligations like work, studies, family and friends. When we do work on Flarum it's because we found some time to do so. Recently @Franz started working for the foundation as a freelancer eight hours per week, but it's entirely up to him when he does that.
In addition listing support hours might make people in need of support abandon their attempt, even when the wider community might offer the correct solution within minutes.