Yeah, that looks about right. Roshi stated that a "right off the bat", untrained KMHMH isn't enough to contend with Chaozu's Dodonpa, which at least to me implies the main takeaway here is that the KMHMH being untrained was the problem, not necessarily the KMHMH itself being too weak of a technique to contend with a Dodonpa from that caliber, with only the Kikoho being the technique appointed by Roshi to leave the KMHMH in the dust.