Extra expected, late arriving (7)
I believe the answer is:
overdue
'late arriving' is the definition.
(I've seen this before)
'extra expected' is the wordplay.
'extra' becomes 'over' (both can mean left over).
'expected' becomes 'due' (similar in meaning).
'over'+'due'='OVERDUE'
(Other definitions for overdue that I've seen before include "(Of library books) late" , "after the time specified" , "Beyond the designated time for payment" , "In arrears" , "Behindhand" .)