The Contract Type defines how the Phase's billing is structured.
Fixed: The phase has a set fee, which can be either Billable (invoiced to the client) or Non-Billable (not charged to the client).
Hourly: The phase is billed based on the number of hours worked. This can also be either Billable (charged based on tracked hours) or Non-Billable (time tracked but not charged to the client).
We used to have Internal as a contract type, but now please use Fixed - Non-Billable instead of Internal.
