Your problem is you don't WANT to do it again for another job. It's also stated that you can level multiple jobs, not that you can level multiple jobs AT THE SAME TIME. Gearing up another job will take about equally long as it took for you to gear up your first job. You just can't do it at the same time. In the end in weeks, months or years from now, you can indeed have multiple jobs on the same character, all well geared.