I drove part of this route today. I noticed a sign at College and Parkway (our I-35BL_S point) on College WB, which is also visible on GMSV, that directs a "Truck Business US 67" straight onto Glenwood Drive. Nothing saying the business US 67 turns north on Parkway back to US 67 as we have it.
I also found it interesting that the I-35 business loop is signed as I-35 BL on the shields in town, but I-35W BL from I-35.