Not sure how you take "in September" (but not "early september") to "mid October" as a maximum of three weeks.

It could certainly be 3 weeks, 4 weeks, 5 weeks, even 6 weeks.   Sept 10 to Oct 22nd would meet the loose definition in the article and would be 6 weeks.  It would also not contradict prior statements by the company.  I am not saying it IS 6 weeks or that it CAN'T be 3 weeks. I am simply say you are assuming something not stated by the company.  

My guess is if it ends up taking >21 days from the first order you will once again jump on your 3 week assumption in early Oct, and complain you were mislead, despite it never being promised by the company.

Simple version:
The only person claiming all orders will be shipped in three weeks is you.