Unable to add filter for "Days Late" to report

Bug / Change Request Description: I need to create a report that shows tasks that are greater than X days late. There is a field associated with tasks called "Days Late" that I would like to filter a custom report by, but when I try to select it in the report filters it doesn't show up. (I've made a workaround where I created a custom form with a calculated attribute that does the same thing) - but I would still like to be able to filter by the tool-provided attribute "Days Late"