Calculating Nutrition Information for Commercial Food Labeling

I'm working on starting a small home-based bakery that will ship food products sold on a website directly to consumers. (Specifically, cookies.) As part of this work, I am designing packaging and am looking into FDA-compliant nutrition labels. Even though this two-person part-time business easily qualifies for an exemption, my preference is to nonetheless provide nutrition information as I believe it would be helpful to customers. At the same time, I believe providing inaccurate information is worse than no information at all. There is an extreme amount of conversation on calorie calculation for personal diets (including here and here), but little I can find on calculation for commercial purposes.

Obviously, nutritional information can be derived through laboratory tests and I have found many such services online.

Another possible solution (that I use for my own diet) is to simply "add-up" ingredient values from their respective labels. This method seems like a great solution but I'm concerned about its accuracy on an FDA-compliant label, especially after baking. I am skeptical of this process because:

• I recall from high school chemistry that frying an egg changes its chemical composition and I'm assuming also its nutritional value, and
• It is commonly stated online that processed foods have altered nutrition values.

My question is in three parts:

1. Are these concerns about the "add-up" process accurate enough to disqualify it from a commercial level of nutrition labeling?
2. Are there other methods I can use to calculate nutrition information accurately enough to meet FDA requirements without needing laboratory analysis?
3. Do you have any other advice on this process or topic for a small business trying to balance providing this information voluntarily and the costs of hiring outside help?

Thank you.