EDIT:
Theres such an option (5secs)
But it would still be amazing to have full control over it
Only thing which is missing. Is the option the set the time when the last beeps of the timer occur. At the moment it is set to the 3 last seconds. It would be amazing if it could be changed to the preferred time in my case 5 seconds. Otherwise its amazing :)
--music-- about Seconds Pro Interval Timer, v3.0.2