Running time difference between DVD and Blu Ray

[manford7]

Hi, can anyone tell me this.

Why is the running time posted on the UK BLU RAY DVD release for the same new movie released day and date is sometimes longer than the UK DVD release for the same version.

For example, on the cover for brand new release 17 AGAIN, it is 97mins on the UK R2 DVD and 101 mins on the UK Region B BLU RAY DVD.

Another example, WATCHMEN new UK DVD-155mins yet WATCHMEN new UK BLU RAY DVD says 162mins. I have seen more like this.

I know when movies converted from American NTSC format have a 4% speed increase for the UK PAL system so a 100 min movie on American NTSC DVDs is about 96mins on a UK PAL DVD.

Does the speed difference not apply to BLU RAY hence the longer running time is the same as the US DVD/Blu Ray discs????

Hopefully, someone with technical know how can clear up this as it puzzles me.

Thanks.
Andy
manford7