Hello Eliza,
The calculation is done on the Lose Focus on the Amount and Probability (%) fields. See the screenshot below that shows the action from the Amount field. Are you using the default screen for your opportunities? CRM_EditOpportunity is the name of the default screen. When you refer to the "face values show correctly", where are you seeing the value?
If you are using the default screen, give Method support a call at 1-888-925-6238 x2. If you are using a custom field, something may have changed for the Lose Focus actions. Also, if you are viewing the pipeline total on a grid, make sure the grid is refreshing to get updated values.
Greg