You're going to have to explain the logic that's led you to this conclusion as it looks to be well off the mark. I think you're crediting Cameron for a strategic move which his actions simply don't support. In fact, I can't see one scrap of evidence that Cameron has done anything to promote 'Yes'.
If he wanted Scotland to vote yes, he's had plenty of options available to not only encourage them to do so, but to guarantee it.
Ultimately if you think Cameron is trying to work the electoral arithematic, and you're crediting him with an astute strategic brain, then you're going to have to explain why he panicked on the strength of a single opinion poll, and within a few days had pledged devo max and about £1000 per household that he'd previously rejected (dependent on who you believe)? That's not the behaviour of a man who is tacitly encouraging yes, nor is it the calm and calculated behaviour of a man with his hand on the tiller.
You might choose to recall that Cameron had a pledge in the coalition agreement to reform the electoral boundaries of the UK which would have netted him about 25 more seats. In order to do this though, the Liberals made their support conditional on reforming the antiquated House of Lords. The Tories didn't keep their side of the bargain, and so the Liberals withdrew their support for the boundary changes.
The next election will be fought on the old boundaries which favour Labour. Cameron made what you might call in a principled decision (though heaven knows what he saw in the House of Lords) but ultimately he made a bad tactical decision. He's done the same now with Scotland and there will no shortage of his own backbenchers (English) who are going to be cheesed off with the concessions that he's made to Scotland when the dust settles and they have time to evaluate who the winners and losers are.
You might recall that about 3 years ago in a Q&A session in California, Salmond let slip that devo max was perhaps the best outcome for Scotland. Why wouldn't it be. He gets just about all trappings of independence, whilst still falling under the UK umbrella should he be struck by a crisis. Salmond wanted Devo Max on the ballot form as a third option. Cameron denied him this and called his bluff (similar tactic used on the AV referendum). In the end Cameron blinked at the first sign of an opinion poll that went the other way and gave Salmond what amounts to Devo Max. Furthermore he's had to suffer the indignity of Gordon Brown penning it, and delivering it. Brown's profile has noticeably risen in the last week, and with it, the No vote stablised
Cameron is not only going to have explain all this to his MP's, he's also got to convince them now that he's the hard man, the canny operator, and the astute tactician who can deliver a renegotiation of the Lisbon treaty. He's damaged goods as of tonight (or will be if the Yes vote collapses). He'll have been seen to have been comprehensively out manouevred by Alex Salmond and the man who blinked at an opinion poll
If it its a narrow victory, it's difficult to see how his own standing will have been enhanced. Ultimately he'll have had to rely on Gordon Brown to save him. He denied Salmond Devo Max two years, and then conceded it to him 2 weeks ago
