In my experience, they will not upgrade you if you send in a broken rod. If you send in a broken rod, they give you a rod of equal price, whether you pay the $100 or they deem it their fault and they send it you for free. Why they won't let you even if you volunteered to pay for it, I don't know.
"If people concentrated on the really important things in life, there'd be a shortage of fishing poles." - Doug Larson