subtitle position change

[Digiface]

when i watch movies,sometimes subtitles goes higher with some lines. is this "problem" in subtitle file or in BSPlayer?

[adicoto]

I've seen this happening when lines are overlaped:

(100)(200)This is the first line that ends at frame 200
(190)(250)This line should stahrt at least at frame 201, not 190

In this case when using vobsub, subtitle lines goes higher and higher.