The important piece here is, though, that both films were developed to similar overall contrast. It isn't until you do precisely that, that you can compare two films anyway. Then, of course, when you start to push the limits of what the film is capable of, FP4 will record a little bit longer range of tones, but will also react to developing changes more readily, so that while you can lean on the film a little bit more at the time of exposure, you have to be a bit more careful developing it.
Anyway, one film, two films - whatever. Just as long as we are consistent with what we do, and we closely study what happens when we use our materials in different lighting situations, and compensate adequately, the reward is going to be fantastic prints. The best thing of it all is that the results will be more because of what we know about the film(s) we use, and the satisfaction we can take from that is tremendous.