Totalled up at last, with no case (2,3)
I believe the answer is:
in all
'totalled up' is the definition.
('in all' can mean in total)
'last with no case' is the wordplay.
'last' becomes 'finally' (synonyms).
'with no case' says to take the centre (outside letters form the word's case).
The central letters of 'finally' are 'IN ALL'.
'at' is the link.
(Other definitions for in all that I've seen before include "Everything considered" , "Taking everything into account" , "Completely" , "With everything counted" , "Taken together" .)