If there is but one German cruiser (not AMC) then it can take any and all merchant points. But this is best viewed in conjuction with the coaling rules. This makes it advantageous NOT to take all the points at the first opportunity if there are multiple ships/squadrons that can reach that zone in later segments of the same turn. This is because a single merchant point will provide coal for an entire squadron.
Excellent point, thanks for the insight.