Ken I noticed you're in KC. I'm also in the KC metro area on the KS side.
When I went on my trip in September they were shipped on August 10th from Davenport, FL and arrived at my house on August 14th which was 2 days early. My trip started on September 8th, 2017.
I was sent an e-mail when the MB's shipped and then about 12 hrs later tracking information showed up.
You might still see if you have tracking information to see when they were shipped out. It could have been a misrouting, a delay at your local post office, weather related issues, etc. I wouldn't anticipate it always being an issue. For mine the MBs bypassed the KC post office which usually packages goes either to there or to the Lenexa post office before being given to my assigned local post office. They just went straight to my assigned local post office.
Glad you got them in time though!