Warren in Lancaster, PA
No, on the contrary, I conclude that higher cutting angle is an important requirement in achieving good performance on interlocked, hard woods. However, the chip breaker is also a factor in improving performance. It remains, however wood dependent.

I have been using the double iron for interlocked grain for more than 35 years. The double iron plane was designed for this type of work. A high angle plane is unnecessary.

Here is what Samuel Carruthers wrote in 1767: