Same tenant - different location

Corporate credit is nice - maybe. What is interesting is that a national tenant in Colorado, such as Walgreen's, will sell at a 7.5 cap rate. While the same corporation who has a store in San Diego, will sell at a 6.0 or lower cap rate. The checks come from the same national office. The quality of that ability to pay debts is the same. Then why the difference in value of the investment? Comments?