idea is: When spread is low and volume is high, then price is well accepted and will be retested in future. Areas without such "market efficiency" will be passed fast without stopping or rejected.
Seems like a hybrid of VSA and Volume Profile with darker areas merely depicting areas of congestion and light areas as pass throughs. I'm not tracking with the adjective "cheap" though. E.g. your 1425 darker blue area above could be considered "expensive" could it not? Or am I missing something.