I've heard, but have not been able to verify
That's a very interesting rumor CTTC. Most of the info you are receiving seems to be on target.
Picking up all the bread crumbs...
The first payment $3.7M. Probably investment or stake by LLEG early in the project (e.g. buying the 13 yr old broiler) was $1.2M, and bought out by Cate. Subtract out from the $3.7M, and you have the two $2.5M payments.
The second part of your story on re-engineering thickens the soup. You have Cate agreeing to pay LLEG $5, not only for the bureaucracy (where $5M is sort of expensive paper pushing), but also for engineering a solution. After all everyone knows Bart is an expert due to his past experience of running an electric producing plant. For whatever reason it doesn't fly, and Cate now has to turn around and hire in a new engineering firm (B&W?). Maybe this was the time period when the plant MW output goal was increased? End result they deduct off the additional engineering expenses from the final payment.
Presumably Cate will defend its position by indicating LLEG&HOMELAND muffed it, causing Cate higher expenses. Trot out B&W to support their position. Extremely weak position for LLEG to be protesting. I see there is the suggestion by Matt, a lawsuit over the difference will be worth the missing millions to LLEG? Not a chance.