Accountant's concern (3,4)
(Another definition for net cost that I've seen is " ultimate damage".)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">accountant's concern</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for books that I've seen before include "Tomes, volumes" , "Reserves" , "Reserve tickets" , "See 1" .)