I would try the same film in both cameras for a while, after checking the lens on the Rollei. Exposure can affect contrast if it's off far enough, but the real control for it is development.
At some point with a roll in each camera, shoot a simple composition with large areas of various tonal values with both cameras, ensuring no change in light between shots. Develop both together if you can. It may tell you something.
In any case, many folks will advise one film and developer until things are predictable.