Crinkle Conundrum

My Betty Crocker cookbook touts the following recipe as being low-fat.
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Chocolate Crinkles

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Ingredients:

2 cups sugar

1/2 cup vegetable oil

2 tsp vanilla

4 ounces unsweetened baking chocolate, melted and cooled

4 eggs

2 cups flour

2 tsp baking powder

1/2 tsp salt

1 cup icing sugar

Directions:

Mix all ingredients (except icing sugar) in large bowl. Cover and refrigerate 3-4 hours.

Heat oven to 350. Lightly grease baking sheets.

Roll 1 inch balls of dough in icing sugar and place 2 inches apart on baking  sheet.

Bake 10 minutes, immediately remove from baking sheet to cool on wire rack.

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I've made them a couple of times, and they are very delicious. But then this week, with my "Cookie Countdown to Christmas" newsletter I got a recipe for chocolate crinkles... The picture looked exactly like these amazing cookies my friend Shannon used to make. I didn't know that was what a chocolate crinkle was supposed to look like!

Here is Jacob offering me a bite of his chocolate crinkle in September of 2009.
Note how the cookie is flat and light brown. 

Here is the picture that was e-mailed to me.
These look like Shannon's amazing cookies. I don't know what she calls them.

So I compared the recipe to Betty Crocker - IDENTICAL except that instead of 4 ounces of chocolate melted and cooled it uses 1 cup baking cocoa. I thought "hey, that actually makes these cookies easier" and decided to make up a batch last night for a christmas party tonight. I made the dough while the boys were napping (Yes, they were both napping, it was amazing), so that I could make them once the boys were in bed.  I used baking cocoa, refrigerated for four hours, did not grease my baking pans, and baked for 10 minutes. I got about 40 cookies, and they are so chocolatey, moist, and yummy.

Want one?

So my question is... why did they turn out so weird the previous times I made them?