I think his phrasing in that section was at best misleading. It's not 15 rockets, it's 1.5 rockets (one booster, one HLS second stage, one refueling second stag

I think his phrasing in that section was at best misleading. It's not 15 rockets, it's 1.5 rockets (one booster, one HLS second stage, one refueling second stage) used 15 times.