2009 bl 12 fs

[Smanleyman 15]

Ok so on the 10, 15, and 18" bl the fs for both the d1 and d2 are the same, but on the 12 d1 is 35.2 and d2 is 39.8hz. I was wondering if that was a misprint or if someone knew the reason it was so different. I wanted a 12 d2 for daily but that fs seems kind of high especially when im used to the lows of my q...