Welcome to APUG.

On the Rollei 400 for the 1-stop of extra exposure you gave the film personally I wouldn't even change the development process. You will probably just have better detail in the shadows with little if any noticeable loss of detail in the highlights. Many people rate their films at 1/2 box speed for every shot they take.

The reason I say this is that pulling reduces the contrast changes between tones in the scene. When I print low contrast (under-developed/pulled) negs I am typically disappointed with the look; they look grey, lifeless, muddy, chalky.