An exception may be made to the maximum duration for which aid for professional integration is granted, in accordance with the terms and conditions laid down by regulation, either when the aid concerns an employee aged 50 or over who is experiencing particular difficulties which prevent him or her from being permanently integrated into employment, or a person recognised as a disabled worker, or to enable the completion of a professional training course in progress and provided for under the aid granted. The duration of this extension may not exceed the duration of the action concerned.