Pic 12F683 Clock Question

I have used some of the 12F Picmicro range, with the option of the 31Khz int clk.
But intending to use a 12F683 just curious as to why manual only specifies the range on P1 of the manual of 8Mhz to 125Khz, and yet else where P19,P20 etc the LF internal osc capable of 31Khz.
I also seen the 12F683 in some projects and articles that state only a 8Mhz to 125Khz clock capability?.
I would like to know why the apparent contradiction.
Max.