Retainers are very tricky to work with. I wish we could improve a few things so its easier and better to use.

Show remaining hours in billing period according to Start Date. If Max is 5 hours on the retainer project and we track 12 hours, it should show the 7 hours overage and have it billable at the overage rate automatically.

At this time we are having to have a second project for overage and need to be mindful if they are going over on a task and split the task or add tasks to the Overage project. I can't image how this would be scalable with more then a couple clients...