더하기 리습인데 소수점4째자리까지 나오게하려면 어떻게 수정하나요?

;;===========================================================
;  Number plus(98CHO_I)
;  ->숫자의 합 구하기(3자리)
;;———————————————————–
(defun c:np(/ choi d_ts w_os ht ss grpt pt1 n k tot en tv rtv an)
   (prompt “… 더하기”)
   (setq choi (getvar “orthomode”)  d_ts (getvar “textsize”)
            w_os (getvar “osmode”) )
   (setvar “orthomode” 0) (setvar “osmode” 0)
   (setq ht d_ts)
   (prompt “nText Height<“) (prin1 ht) (prompt “>: “)
   (setq ht (getdist))
   (if (= ht nil) (setq ht d_ts))
   (prompt “nSelect number->”)
   (setq ss (ssget))
   (setq grpt (grread T))
   (setq pt1 (cadr grpt))
   (setq n (sslength ss))
   (setq k 0 tot 0)
   (while (<= 1 n)
        (setq en (ssname ss k))
        (setq tv (cdr (assoc 1 (entget en))))
        (setq rtv (atof tv))
        (setq tot (+ tot rtv))
        (setq n (- n 1))
        (setq k (+ k 1))
   )
   (setq tot (rtos (* tot 10000) 2 0))
   (setq an (strlen tot))
   (setq tot (strcat (substr tot 1 (- an 4)) “.” (substr tot (- an 3) 3)   ))
   (command “text” “j” “r” pt1 ht “0” tot)
   (prompt “nEnter text point->”)
   (command “move” “l” “” pt1 pause)
   (setvar “orthomode” choi) (setvar “osmode” w_os)
   (prompt “n합 계 : “) (prin1 tot)
   (prin1)
)