Redmine

Hi all, I'm interested in improving my teams spent/estimated time ratio KPI tracking. How do you implement your filters for this? Currently we're filtering by assignee and milestone, then by showing spent and estimated time options and finally displaying the "totals" row. The problem here is that some tickets are lost because the assignee gets changed or some stray tickets get counted in even though they should not be counted (like personal improvement tickets, etc). What do you use as a solution for getting accurate KPI's? We're thinking of implementing a "responsible developer" field and using it instead of "assignee", but some devs say that it's too redundant. Any good ideas on better KPI tracking are appreciated!