By listening to different info, I think the way it works (but still not sure) is:  Subcommittee  hearing Subcommittee makes a report and send it to the the higher parent committee. Parent Committee look at the Report. If incomplete, they send back the Report to the Subcommittee. If complete, they send the Report to the Senate. After viewing the Report the Senate can ask for a Senate hearing (legal implication). And it's where the real action will occur because Republicans have the Senate.