How do I sum hh:mm cells?

[lemelman]

I have a SS where users enter the time spent on a job as hh:mm. The cells are formatted as Custom hh:mm and are summed using =SUM(OFFSET(INDIRECT("A1"),8,COLUMN()-1,ROW()-9,1)), and that cell is also formatted as Custom hh:mm.
Trouble is, the total is wrong.
For example: the three cells containing 03:40, 20:15, and 02:00 should add to either 25:55 or 01:01:55 (to represent dd:hh:mm), but it actually totals as 01:55.
How can I get a useful representation of the true sum. I don't mind what it is, but is certainly shouldn't be 01:55.

[Pepe Le Mokko]

Custom format the sum as [h]:mm

[lemelman]

Thank you for a very rapid response, that worked fine.