function DecrementArray(var a: array of integer; val: integer= 1): boolean;
var
  i, d, m, len, sum, cnt, old: integer;
begin;
  if val<=0 then begin;
    Result:=(val=0);
    exit;
    end;

  len:=Length(a);
  sum:=0;
  for i:=0 to len-1 do sum:=sum+a[i];
  Result:=(val<=sum);
  if not Result then exit;
  if val=sum then begin;
    for i:=0 to len-1 do a[i]:=0;
    exit;
    end;

  cnt:=0; sum:=0;
  repeat;
    d:=(val-sum) div (len-cnt); m:=(val-sum)-d*(len-cnt);
    old:=cnt; cnt:=0; sum:=0;
    for i:=0 to len-1 do if a[i]<=d then begin;
      sum:=sum+a[i];
      inc(cnt);
      end;
    until (old=cnt) and (len-cnt>=m);

  for i:=0 to len-1 do begin;
    if a[i]<=d then a[i]:=0
    else if m>0 then begin;
      dec(m);
      a[i]:=a[i]-(d+1);
      end
    else a[i]:=a[i]-d;
    end;
  end;

procedure TForm1.Button1Click(Sender: TObject);
var
  a: array of integer;
  i: integer;
begin;
  SetLength(a, 4);
  a[0]:=0;
  a[1]:=40;
  a[2]:=100;
  a[3]:=5;

  DecrementArray(a, 60);
  for i:=0 to Length(a)-1 do Memo1.Lines.Add(IntToStr(a[i]));
  end;