Calculating elapsed time over a (spring or fall) time change

[evp000]

HI,

I was wondering what your suggestions would be in calculating the actual elapsed time between two timepoints when a time change occurs between them.  In the past I've done this manually:

- calculate the difference (in hours) using the start datetime and end datetime. 

-if the start point was prior to the time change and the end point was after the time change, add or subtract 1 hour (depending on whether it's spring or fall).

Would  INTCK('hour',startdatetime, enddatetime) somehow be able to take the time change into consideration?  I realize this is location-specific. 

Thanks for your input.

[Shmuel]

The arguments need for INTCK are not enough.

To calculate elapse hours is depnedet also on place, i.e. COUNTRY and sometime even REGION/STATE.

In some countries the change dates are dynamic according to political decisions, which make it even more complicate.

[evp000]

Ok, thanks.