I am in the middle of a discussion among branding professionals on the subject of brand values and when they should be established. My belief is that they must begin any branding initiative. The opposing view was that they follow the development of the differentiator.
I believe that the differentiator must be based on your existing brand values. Not contrived to match the differentiator. For instance when I facilitate a session, we use the values and personality of the brand to validate the differentiator. If it doesn't stand up then it (the differentiator) won't last because the company has to walk the walk. the brand has to be genuine. To do the differentiator first then come up with values to match it, tears down exactly what the values are supposed to represent. When based on what makes them different, can it really survive during tough times when the temptation to compromise values is at its peak.
When the values are based on stakeholder's beliefs at the very start of the process - then this I believe is the true character of the business and what they stand for. They are the foundation of the brand. Values should span the test of time, not change when ever the differentiator is up-dated to match it.
So for my process, values are bottom up - not top down.
As for corporate brand and product brands being the same, I must also respectfully disagree. A brand is the perception on the street, and that perception of the individual is your brand in their eyes. Take Apple for instance. From a corporate perspective their brand is huge. But when the Newton came out its brand was less than stellar. It never lived up to its expectation. That product's brand was poor compared to Apple's corporate brand. Every company has hits and misses - how could both brands be the same in light of this?