Comparing GoTo Surfing with True Surfing?

Yes, your later movement options are restricted by what you choose to do earlier. I think this reflects what happens in the game physics too :-p

But the whole point of the second wave surfing is just to find the smallest second wave danger given the restriction of trying to go to the first wave point first. You don't actually need to know where that best second wave point is, you just need it's danger as an extra heuristic for evaluating how dangerous the first wave point is. Once the first wave passes you recalculate all the dangers, treating second wave as first wave, third wave as second wave etc. So the actual location of that second wave point doesn't really matter outside of the danger calculation.