^^^^
When I need a bigger build, it's generally for lagers, since I really don't do high gravity beers, but same principle. I've also taken to two packs in a smaller starter rather than one pack in a really big one or stepping up. The latter two options theoretically will result in more new cells, but it all seems to work the same in practice. It's just a matter of what is most convenient or cost effective under the circumstances. That chart is a good starting point, and with oxygen or agitation you'll actually probably grow considerably more. But remember that health trumps count, so don't worry too much about the exact numbers as long as you have yeast freshly grown with nutrient and plenty of oxygen, and you also provide sufficient oxygen in the pitched wort.