Before I comment on your dough formulation, let me bring you up to date on some matters that relate to the Bisquick Original Pancake and Baking Mix.
I spent a lot of time yesterday trying to decipher the Bisquick Original Pancake and Baking Mix. I think what complicated matters is that I was having trouble finding publicly available information that matched the Nutrition Facts for the mix. I concluded that it was perhaps likely that GM uses ingredients made especially for them with specific characteristics that are not reflected in the publicly available data at SelfNutritionFacts and similar sources. After more research, I finally came up with a set of baker's percents that appeared to me to be credible. It then hit me that the unit that makes the Bisquick products is a part of General Mills. So, thinking that the Bisquick unit was most likely using a GM flour, I researched all of the bleached cake flours that GM sells. One that looked promising is the Pureasnow cake flour. First thing this morning, I sent an email to Tom Huff at GM in which I asked him what flours that GM sells might be most suitable to make pancakes. I also asked him if he had a formulation that he could share with me. I told him that I was looking at something that could be used to make a mix that was like the Bisquick mix. I did not expect that he would give me the Bisquick formulation but I wanted to get an idea as to possible baker's percents.
This afternoon, I received the following reply from Tim:
Pancake mixes could use anything from a soft wheat cake or pastry flour up to a hard wheat all-purpose flour, or a blend of these flours. A lot depends upon the eating quality and texture desired.
Attached is an old formula I had on hand using a cake flour.
The pancake formulation had the following baker's percents (I put the numbers in the same order as the Bisquick mix):
100%, Puresnow cake flour
10%, Melted butter
3.5%, Baking powder
The formulation also includes milk and eggs, both of which contribute fat to the total recipe, but I left them out in my summary above so that the numbers would track with the formulation for the Bisquick Original mix. My tentative formulation for the Bisquick Original mix is different from the above but I believe that it is still credible when shortening (partially hydrogenated soy and/or cottonseed oil) is substituted for the butter in the proper quantity and sugar is replaced by dextrose. The 10% figure listed above for the sugar is higher than what I have seen in the pancake recipes I reviewed. It clearly does not fall in the proper place in the pecking order for the ingredients in the Bisquick Original mix.
An interesting sidenote is that the recipe that Tim gave me had an example based on using 32 ounces of flour. When I added up the weights of all of the ingredients in the formulation summarized above, I got a weight of 39.6 ounces. A standard box of the Bisquick Original mix is 40 ounces. In my formulation, I also ended up with 32 ounces of flour.
After settling on my formulation for the Bisquick Original mix, I tried to adapt it to the Buttermilk Bisquick biscuit mix. My tentative formulation showed that there was less fat than what is used in the Buttermilk Bisquick biscuit mix--about 8% less. That discrepancy could be fixed by adding more shortening or, as an alternative, some oil, as you proposed to do (although I think you may be shy on the amount). I also concluded that you were perhaps shy on the amount of buttermilk powder, the dried egg and the soy flour. However, these ingredients are so far down the list in terms of baker's percent, any deficiency in these ingredients might not even be missed. As noted earlier, I suspected that the amount of baking powder was greater than normal, or at least greater than what I believe is used in the Buttermilk Bisquick biscuit mix. Even then, "normal" is somewhat relative. In reviewing pancake recipes, I found a fairly wide range of use of baking powder. In fact, in one of the recipes that I saw on the back of a box of Bisquick Original mix it says to add more baking powder to get super fluffy pancakes.