It sounds as if it will have the capability of supporting 6 people eventually. If there is a need, and there surely will be, they can re-configure the thing. And to get something built near the budget and near the deadline would seem to be paramount.

After it's built some future budgets might be more generous. It would be a shame to stick to 6 people, run way, way over budget and very late, thereby completely discouraging the public.

Another factor may be that the longer the US doesn't have the capacity to reach the ISS the longer we'll be on other, less expensive, political entities. The public could get used to that.

Of course, I'm just guessing, one big surmise. My motto: Often wrong, never in doubt.

Arf