Bolt length

Hi
i have need three nuts for 16" & above flange size and two nuts for below 16" flange size. in this case how do i consider extra length of nut?


Under Xtralength 0mm
Bitems nut (for extra nut)
Bitlength 35 mm (nut height)

But this 35 mm is not add when i generate isometric........


this is possible in old bolting method
plz help me