BS.Player's "Jump" feature is not normally controlled by arrowkeys but BS.Player's function "Seek" is. (Note "Jump" and "Seek" are different features.)
Why then the
(abt) 8 secs interval when using arrow-keys? Well probably you've selected option "Seek by keyframes (AVI and MKV files)" under
(rightclick >) Options > Preferences > General [General settings].
"Jump" feature's default is 10 seconds.
You can set a different time at "Seconds to jump" which is almost at the very "south east" corner of the same window, i.e. [General settings], as indicated above.
The default controls for "jump backward/forward" are the [,]/[.]-keys.
You can define different keys (separately for windowed and full screen mode) under "Key definitions & WinLIRC", but when doing so avoid using keys which are already in use for another option!
