I would hope for better curve shape than the one with the sag in the middle.

The 6 or 7 minute curves are more realistic here:

http://www.kodak.com/global/en/profe...4017/f4017.pdf

There is no magic bullet developer, only one that gives the best results. If the saggy curve works for you, then it is fine, but I prefer the straight line which gives me better results and is what the film was designed for.

PE