Undefined CoS’ are issued on an annual basis. This is called your ‘annual allocation’. You can apply for an annual allocation via the Sponsor Management System.
If throughout the year, you need an additional undefined CoS, you can apply for more via the SMS however it can take weeks for this application to be dealt with by UKVI.
A defined CoS has to be applied for each time you need one for a specific role to be sponsored. This application is also made by the Level 1 User on the Sponsor Management System. You can apply as and when needed and applications are usually dealt with within 1 working day if they are straightforward.
