Good Afternoon, Ronlamarsh,
As you've noted, it's not unusual to have a somewhat uneven progression in contrast steps, especially toward either extreme. Frankly, it isn't worth worrying about in most cases. First, the vast majority of your negatives will probably require one of the middle filters. Second, if not, then you need to make adjustments in your film development; that's a lot easier than trying to get good results from very flat or very contrasty negatives.
Konical