Celtic Heroes

Hello . My ranger is Dlynn, lvl 105. Both Bow Ability and Ranged combat are maxed at 1050. It seems to me that the duration for Rapid Shot at its current rank (29/25) lasts just as long as it did at 15/25. Does the duration go up at intervals such as 5 pts, 10pts, 15 pts? Or is it a huge gap for a small increase like 1 seccond increase every 15 pts? I have been unable to find much of a diffrence in duration regardless of points into the skill. Any input would be greatly appreciated . Thank you!

I found out that the more points you have in rapid shot the faster the cooldown as it carrys in through your cooldown i got 39/35 on rapid and when it stops it only takes 20 seconds to cooldown from when it finished, and it lasts around 27-29 seconds