This is a pretty safe general rule, but it is not absolute. I had a brand new truck < 6 months old where I was hit from behind in stop-n-go traffic. The insurance company did not want to total it because the repair could be made for less than the value of the total. I asked how a frame could be repaired, and they just said it can be done. My counter was that the vehicle would now show frame repair and would have no value for trade-in nor would someone other than less than reputable dealers offer a car with repaired frame damage.
So, depending on the insurance company (Progressive was pushing for the repair. I hate Flo), some will argue against frame damage being an automatic total.