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
a2 =Zeit(87;0;0) (this is LibO 220.127.116.11, it should be (like in 3.6.4 lin x64) 87:00:00 (or similar, according to the formating.
Should (3.4.6): -7:00:00
IS (18.104.22.168): 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 :-)