A bit inaccurate writing in that report. A third of what? It costs 1100yen to Hamamatsucho from NRT now on the Keisei/Toei lines and they do a lot more than 4 roundtrips.
The answer is fairly obvious: they are comparing their bus fare with other companies' bus fares. They're not comparing their bus fare with limousine, taxi, or train fares. The well-established provider's Friendly Limousine bus costs 3000 yen for the same route.
So, the reporting of the 1000 yen fare being a third of the standard fare is quite accurate. And quite obvious.