It’s not about throughout. You want previous intersections and ramps to be free. The extra lane is car storage space. If one lane is stopped and the other is free you absolutely move up to the merge point. Safely, mind you. The speed limit is way too fast, 30-40 kph is enough. Merging early causes shockwaves that turn into full blown stops upstream. Plus you block the whole lane until you’ve merged.
I’ve done traffic control systems for almost a decade so I actually know a little about the subject.