Yes, that's wrong. The author was talking about that fact that Urdu has more letters than standard Arabic, mostly additional diacritics etc, which makes enteri

Yes, that's wrong. The author was talking about that fact that Urdu has more letters than standard Arabic, mostly additional diacritics etc, which makes entering it with an Arabic keypad/keyboard painful. Both Naskh and Nastaliq can be encoded using the Arabic block in Unicode, it's just that Nastaliq's vertically stacking nature makes it difficult to deal with in computer systems that expect clean rows of text.