I have been asked many times how to get the task time phased data from the PSI. Unfortunately there is no way to get this through the PSI. I suggest that you either go to the RDB for this information or the cubes. Here is a quick example.
I created a project with one task and broke the work down over a week:
I saved and published the project so that it would make its way into the reporting database. Here is the query I wrote to retrieve this data:
SELECT MSP_EpmTask_UserView.TaskName, MSP_EpmAssignmentByDay_UserView.TimeByDay, MSP_EpmAssignmentByDay_UserView.AssignmentWork FROM MSP_EpmAssignmentByDay_UserView INNER JOIN MSP_EpmTask_UserView
ON MSP_EpmAssignmentByDay_UserView.TaskUID = MSP_EpmTask_UserView.TaskUID WHERE (MSP_EpmTask_UserView.TaskName = 'Task 1')