What goes to block army career, perhaps (7,6)
I believe the answer is:
'what goes to block' is the definition.
(charge given to all residents of a block of flats)
'army career perhaps' is the wordplay.
'army' becomes 'service' (military service).
'career perhaps' becomes 'charge' (career can mean to charge around).
(Other definitions for service charge that I've seen before include "Restaurant bill add-on" , "Restaurant bill addition" , "Additional restaurant fee" , "Part of bill" , "it may mean that extra 10%" .)