When you try to make an outbound call but, for example, primary trunk is unreachable, PBXware will automatically try the next option in 'MiniLCR' or 'Default Trunks'.
This happens without your knowledge and you may be paying a more expensive rate, as rates vary from one provider to another.
To avoid this, go to 'Settings: Default Trunks' and set 'Secondary' and 'Tertiary' Default Trunks to 'None' (i.e. 'Please select'). The system will then use the primary trunk only.