The duration field in CRM accepts values in minutes so for 1.5hrs you really need to type in 90 and that would automatically show 1.5hrs in the drop down.
Please check that the value is correctly entered in the duration.
HTH
Sam
Dynamics CRM MVP | Inogic | http://www.inogic.com/blog | news at inogic dot com
If this post answers your question, please click "Mark As Answer" on the post and "Mark as Helpful"