Police Certificates DV 2019 Europe and US Question

Hello all,

My husband has been selected for the DV 2019, and we are in the process of putting together all the paperwork required for processing.

I have a couple of questions regarding the police certificates needed that might seem obviously, however I would like to clarify it with you here.

As per the guidelines, a police certificate from the country of nationality is required when you resided there for more than 6 months. More than 6 months since... your last visit? I left my home country (Europe) when I was 20 years old, but visited it multiple times since then, however for a duration less than 6 months. In this case, I wouldn't need to request it, right?

Also, for the US, it is mentioned that present and former residents of the United States should NOT obtain any police certificates covering their residence in the United States. I was living in the US on a F1 and J1 visa for several years (now I am back in Europe), however with breaks in between. In this case, I was considered a resident, and I don't need to get any police certificate?

I apologize if my questions might seem too obvious for some of the experienced users on this forum, as I prefer to get a second opinion on my understanding of the guidelines, just to make sure we are making the right decision with requesting the right paperwork.

Thank you in advance for your answers.