I do not wish to dwell on these differences, other than to note that they show the dangers of coming up with a general explanation of exchange rate movements which turns out to be only applicable to one country or one period of time. The second explanation relies on the well-known tendency for exchange rates to be driven by momentum.
That is - once a trend has been established, for example, by the events in the first half of  BIS Review 101/2000  2  the year - it tends to continue and thereby to overshoot the level implied by fundamentals.