Blindspot Short of 39'

[p209chief]

Ram advertised 39' of coverage. However, I tow a 35' bumper pull travel trailer and have noticed that the left side blind spot indicator falls at least ten feet short of the trailer's length (can see pretty well where it picks up from early morning and late afternoon shadows). The right side covers the full length, but that's usually the shoulder since I've found gas mileage takes a big hit much above 60 MPH and stay in the slow lane. It's the left one that I really need when folks are roaring up on the driver's side and I'm trying to get out of a lane that's ending or exiting. So much for whining. Has anyone else noted this?? I took it to a dealer and they nicely said they sympathized, but that both were in factory specs ... hope for a software update that might fix it. )c