Filling DS-156 online

[papudi]

Hi,
In online ds-156 form, question 29 and 31 there is additional box, must I fill this box with "NONE".
When I fill additional box with "NONE" in 3 pdf page appear "NONE" - is this wrong

[immihelp]

read https://www.immihelp.com/us-visa-app...n-form-ds-160/