Sorry, it is rather late, feel free to change the heading. 1 Open a new Calc document 2 Write in ( and format with [HH]:MM but that is not important, it just need a time formatting a1 80:00:00 a2 =Zeit(87;0;0) (this is LibO 3.5.2.2, it should be (like in 3.6.4 lin x64) 87:00:00 (or similar, according to the formating. a3 =A1-Zeit(87;0;0) Should (3.4.6): -7:00:00 IS (3.5.2.2): 65:00:00 2 times confirmed on different systems
Markus reports - this is an ODF 1.2 compatibility feature as defined in the spec. Sorry :-)