Task reports with summary task data must be run using the option to "Show only top-level summary tasks and tasks" so that reporting data on the bottom line totals to the correct amount. When using this option, all bottom-line total information in the report is correct because the top-level summary task data is inclusive of all child tasks and the top-level tasks with no summary tasks are included as well.
An important caveat: the report cannot contain a list of every task and summary task under most common project work breakdown structures (WBS). The only condition under which all tasks and summary tasks would be individually listed in the report would be if all of the included projects had no summary tasks.
This is particularly important when choosing to mark tasks as milestones. A milestone report is a task report, so milestones should never be summary tasks for cross-project milestone reporting purposes. Summary tasks are allowed to be milestones for compatibility with other software applications, but this is not a typical recommendation for a WBS in general. It is definitely not recommended in Project Insight.
Summary tasks and milestones are used for distinctly different purposes. If the completion of a summary task represents a milestone, it is best to separate them by leaving the summary task alone and making the milestone a separate task which is a successor to the final tasks of the summary. The milestone can be assigned to the project manager who controls the milestone completion through exclusive access to the 100% completion update of the milestone task.