The investigation has many gates to get through. As I understand it yes the BI is normally complete within 30 days. However there are varying levels of review based on information brought out by the BI. Each one is unique. I have found those living in one address for many years, having a long time job, excellent finances and zero derogatory info, no drugs, no arrests, no terminations etc, they move somewhat faster but not consistently and measurable so. Right now 8 to 12 months is my standard wait from the day I scan to the clearance division, to the day I get notified it was approved. So even though the investigation itself is complete, it could require higher level review before granting or denying. The two biggest reasons clearances are denied is non legal drug use and finances. I don’t know your entire situation and can only comment on the info provided. DHS may very well have a higher standard on drug use, or it is based on your age and other factors. What specifically did the statement of reasons say was the reason you were denied? Often they are written in the worst possible manner. Did the investigator understand what you were trying to communicate? Did he list it as more severe? Were there other factors listed?