It's encouraging to hear from educators out there who understand communicating the value of problem solving and comprehension is more important than rigid adherence to methodology and procedure.
I remember the most useful aspect of my secondary school education (12-16yr) was learning how much I liked problem solving. However I came to this realisation through solving various simple math homework problems without following procedure (procedures which I remember finding particularly irritating for not explaining themselves) only to be lectured on how I had not followed the rules in spite of arriving at the correct solution and understanding the problem (albeit not well enough to figure out how the procedures worked).
My teachers did exactly the opposite of what the above quote is saying - they insisted on one approach, without explanation, and it totally alienated me from math at the time. Thankfully I was never a very "good student" and it didn't dissuade me from enjoying the problem solving aspect, but it did leave a lasting impression of "i'm not good at math".