Naci background check?

Hi, I've previously posted but I have another question. It's been 3 weeks since I received my offer and NACI background check request. The only thing I've heard since then was a signature request to pull my school transcript. Is this normal? I've worked for USPS twice before so I know it takes awhile but they have never request my school transcript before. This is for a electronic technician job if that matters. Thank you in advance! My dad who is a PM thinks it's just because I would be working on government equipment and can do real damage if im not who I say I am.