Appearing this week at the Goldman Sachs Technology & Internet Conference, Microsoft CFO Peter Klein continued with the firm’s recent spate of transparency, openly discussing the difficulties it has had getting Windows 8 and Surface to market. But maybe Klein was a bit too transparent: He also noted that Microsoft has “no Plan B” for mobile, suggesting that if Windows Phone fails, the company has nowhere to turn.

Klein started off with a discussion about Windows 8, noting that the “flexibility and scalability” of the OS lent itself well to any device size or form factor. Answering a question about the emerging market for smaller tablets with roughly 7" screens, Klein said Microsoft was ready.

“I think we’re really well set up to deliver the most versatile set of experiences across form factors, whether that’s 4 inch, 5 inch, 7 inch, 8 inch, 10 inch, 13 inch,” he noted. “[Microsoft and its hardware partners are] well set up to respond to demand, as we see it.”

And that “flexibility and scalability” occurs in the software as well. “[We have] the same core code base driving form factors from 4 inches all the way up to 27" all-in-one [PC]s, and everything in between,” he noted. “And now applications can scale up or down based on the size of the form factor [as well].”

With a wellspring of new touch-based devices now hitting the market, Klein suggested that Microsoft and its partners had finally overcome the supply issues that dogged them when Windows 8 launched late last year. Today, he said, we’re seeing the type of diversity one expects of the PC market, and more devices are coming to stores all the time.

Klein also hinted that it is bringing its Windows client and Windows Phone products closer together—a move I called for explicitly this week in "Hey, Microsoft: It’s Time to Pull Phone into Windows." While glossing over the technical issues in today’s developer tools, he said that it was easier than ever to write apps that ran on both Windows and Windows Phone, and that these two systems would continue to move closer to each other, benefiting both developers and users. "We are getting closer and closer every day to write once and run anywhere,” he claimed.

Klein was asked what Microsoft would do if Windows Phone—currently still hovering around a negligible 3 percent market share—failed. Was there a “Plan B”? “We’re very focused on continuing the success we have with PCs and taking that to tablets and phones,” he said. “It’s less ‘Plan B’ than how you execute on the current plan. We aim to evolve this generation of Windows to make sure we have the right set of experiences at the right price points for all customers.”

When asked whether Microsoft would port its Office suite of applications to Apple’s popular iOS devices (e.g., the iPhone and iPad), Klein offered nothing new: He said that the firm was of course evaluating the opportunity and that the tradeoffs—the success of Office vs. removing a key advantage of Windows products—was fairly obvious. My sources tell me this product is in fact complete and that Microsoft will release Office 2013 for iOS before mid-year.

Finally, Klein also discussed Microsoft’s $2 billion loan to Dell, which many have mischaracterized as an investment. “We have a long history of participating and supporting the ecosystem, and that takes different forms,” he said. “Oftentimes it takes the form of co-marketing, sometimes in helping with development. In a very dynamic industry, our ability to support the ecosystem—particularly the ecosystem that is innovating on our devices and platforms—is a good thing and something we will continue to do.” He doesn’t believe Microsoft’s other partners are upset with this aid.