Perhaps I misunderstood what Gwynne was saying. I thought that "launch costs" would be the cost of launching a rocket for SpaceX, rather than the price that they set for customers.

Perhaps your correct though, the quote is a bit ambiguous.

"It's saving 90% in launch costs, but we're only passing 30% of the savings along to the customer" doesn't sound very good in a press release.

Plus their launch backlog is already pretty full since they are undercutting all the incumbent providers... no sense in decreasing their margins if the current prices are very competitive.