Discrepancy of observation length

[Shinnnosuke2]

Hi all,
I tried to make a .fil file following the document.
The example in the document shows tsamp of 256e-6 and 8192 time samples, which equals the total time is about 2s.
However, I see that the observation length is 16.8s using SIGPROC header command.
Am I misunderstanding something?

Thanks,
Shin