P.O. Deep black. Somebody Know?

[proyectdf]

Hi to all.
I just have my QC pictures from my next Omega P.O.
Deep Black VSF.
Somebody knows to understand the test watch ?
Rate: +7 s/d. That appears to be right. Accuracy Ok
And here is the doubt: The period value is 4s
I am get used to see 12 s instead 4 s.
Somebody knows what means that?
It is a good value ?

Thanks!!