Can't change image duration correctly, bug ?

Hello,
I'm trying to change the image duration of a clip to 0.12 second but when I write 00:00:00:12 , Davinci changes automatically to frame rate = 12. But if my timeline is 25 frames per second, 0.12 sec is 3 frames and not 12 ...
Is it a bug or am I completly lost ?
Thanks
I'm trying to change the image duration of a clip to 0.12 second but when I write 00:00:00:12 , Davinci changes automatically to frame rate = 12. But if my timeline is 25 frames per second, 0.12 sec is 3 frames and not 12 ...
Is it a bug or am I completly lost ?
Thanks
