Whenever I have tested films/developers I have always tested including the shoulder region because it is important in my work. I've done this with several films and developers - over and over. There are quite a few variables to consider and both the shape of the shoulder and where it begins are subject to manipulation. The only rough generalization I would make is that the films I've tested tend to exhibit their longest straight lines when developed to an approximately normal CI. Underdevelopment tends to shorten the straight line due to increasing compression on both ends, and gross overdevelopment moves the shoulder to the left for obvious reasons. On the underdevelopment side, different developers and techniques can have some effect on the curve shape.
I would suggest you simply move on from your overexposure error.