Correction in DS-160 after form submission and VISA interview scheduled?

[optimusPrimeXY]

I have submitted DS-160 for my parents and scheduled the B2 VISA interview. The interview is coming in a week.

Now i discovered that there is a mistake in the question "Have you traveled to any countries within the last five years?" which is supposed to be YES but i replied NO in both of the DS-160's (mom's and dad's). Retrieval now means a new DS-160 and possibly duplicate VISA fee and new appointment!

How grave is the mistake? Is it safe to continue now with the current DS-160 and report the same during the interview? Their flight is in 10 days after the visa interview. So if the visa officer gives an option to correct the information how does it work and how long does it take? Denial on this ground will be devastating, so again how grave is this mistake?

Thanks in advance for all the suggestions.

[Ideal sol]

You should fill genuine, accurate and truthful information in DS160 form. If you fail to do so, may end up disqualifying for the visa.

Contact the U.S. Embassy or Consulate where you applied for specific instructions.

This is my opinion, not a legal advice.