After your TPC-H Throughput test is completed. Run Reports and open up your test results. Go into the folder Results | User Load | Transaction Statistics. When you click on Transaction statistics all the streams should appear on the right hand side. Sort the column for Avg Transaction Time. Take the longest running time and that will be your Maximum Stream Time.
For more tips and tricks regarding Benchmark Factory, visit the community site at http://www.quest.com. Click on the Communities tab, Community Sites, Benchmarking Community.