Invoice computed properties not updating.

[MatthewDorner]

Expected behavior:
Various totals and calculated values on "Edit Invoice" page are correct and update instantly as user changes info.

Actual behavior:
A, G, C: Update as expected whenever you change the quantity or price of a line item.
B, H: Only update if you refresh the browser and then view the invoice again.
D, E, F: Show zero no matter what.

OS and Browser:
Ubuntu 16.04, Chromium, Firefox

I tried to figure this one out but the computed properties are pretty confusing. I would keep on it if somebody wants to help though. Also, the line item "Delete" button doesn't work on this page because it's trying to call an action showDeleteModal() like a function from inside another action, whereas if you replace it with send(), it works.