No actually that's incorrect. And besides the point since with a clean 130 Mbps connection, which can do 50 - 60 Mbps of throughput, you can easily handle a 50 Mbps internet connection. Bonding another channel when you're getting 5 Mbps isn't going to help that much.
The Wi-Fi Alliance pointed out that the second equation in part 10.15.3.2 shown below adds an important behavior. It essentially says that if either the primary or secondary channel of a 20/40 router or AP is the same as either the primary or secondary channel of a 20/40 neighbor AP or the operating channel of a 20 MHz router or AP, then 40 MHz operation is permitted. The reason for this is that since the two APs are operating on the same frequencies, each one can understand the other's transmissions and can coordinate transmissions properly.