Preheat oven to 350 degrees.
Spray a 9 x 13-inch baking pan with nonstick baking spray and set aside.
In a large bowl, mix the pumpkin, milk, eggs, both Splenda products, 5 teaspoons of the pumpkin pie spice, vanilla extract, and salt until well blended. (I prefer doing this with a wire whisk.) Pour mixture into the prepared baking pan.
In a medium bowl, using a wire whisk, mix the cake mix with the remaining pie spice mix; sprinkle evenly over the pumpkin mixture in the pan. Sprinkle the chopped pecans over all.
Melt the butter and mix with the oil; drizzle over the pecans.
Bake at 350 degrees for 50 minutes or until golden brown.
Garnish with whipped cream and/or spiced pecans, if desired.
Note: This is my diabetic version of a McCormick® recipe I got from my grocery store.