That is correct, if you raise interest rates you get a sudden and immediate increase in the value of your currency, followed by a slow decline, instead of a sudden decline followed by a long term increase. That's why the increase could be misleading, if XYZ currency goes from trading at the same price as the $US to trading at 1/10 the price and slowly increase up to 1/2 it is true that at some point over the life of the currency it has increased 500% but I wouldn't call that an argument in favor of the economic health of the country. That's essentially what would happen if you drastically slash interest rates as Japan did.