How can I improve this master detail/grouping UI?

In my application, I have to represent a Work Order entity that has N Work Order Sections and each section has M sub-items. Currently, I'm representing this like so:

Each Work Order has a bunch of fields (not shown). Then I've got a tab strip showing the sections, and each section has fields (not shown) and the M items.

I'm using tabs to indicate N children, and an extra dummy tab to add a new entity to the list. And I'm using a link to enable deleting the current entity in the list.

I'm trying to find a more elegant and unified way to represent the Add New and Delete Current actions, keeping them physically together. What would be a good way of doing this?

Or, is there an entirely different and better way of capturing these master detail relationships?