I agree with CliftonGK1 in not loosening the tension bolt. You actually might want to adjust the saddle height if it is replacing a saddle as some platforms sit higher or lower on the rails than others (not by much usually, but it could make a difference).

Some saddles also work better than others regardless of how many people rave about a particular one. Also some Brooks are great right out the box (mine was although it is a different style than yours) while others may take a while to break in. I haven't experienced your problem and mine is tilted back slightly.