That's a very good observation about the dates each month being similar.
If we could prove that RK went on the same day for that area, and he reported seeing the remains first on August 11, and then found them on December 11, it would seem he worked the area on Suburban on the 11th of the month. I don't imagine it would take him more than a day for the subdivision, but I could be wrong. So it looks like his day for the area would be the 11th? I think the incident above took place on October 9, but a day or two difference might not mean much.
Also, I will look this up to verify, but IIRC, RK was reassigned after August and did not return to this particular route until December, the first day back being December 11. I am not sure exactly when he was reassigned, however. If someone else has a better memory than I do, please jump in, TIA!