Absalom Energy's 14% coupon rate, semiannual payment, $1,000 par value bonds that mature in 30 years are callable 5 years from now at a price of $1,050. The bonds sell at a price of $1,353.54, and the yield curve is flat. Assuming that interest rates in the economy are expected to remain at their current level, what is the best estimate of the nominal interest rate on new bonds?

I know the answer is YTC = 6.47% and how to get that. Why when it asks for the nominal interest rate do we calculate YTC instead of say YTM?