The impact of this currency and commodity volatility in part was a revision to our full year effective tax rate due to the revised full year earnings mix, which resulted in a cumulative year-to-date tax expense adjustment in the third quarter. For the fiscal month just ended last Friday, October 28, approximately $12 million of the $31.5 million of other expense has been recovered due to improvements in metals and currencies since the end of the third quarter.
Turning to Slide #7. We chart the movement of copper and aluminum to illustrate the volatility experienced during the quarter. Copper prices declined sharply at the end of the third quarter to $3.15 per pound, a net drop of 30% from the quarterly high of $4.47 per pound established in July and a 20% decline over the final 15 days of the quarter. As you can see, aluminum prices followed a very similar trend, which is not inconsequential, particularly from a top line perspective as a mix of aluminum-based product shipments increases as our aerial transmission businesses in Brazil and North America continue to grow. Consistent with what we said in the past, we believe this extreme volatility affect the buying behavior of some distributors in the third quarter.
In addition, certain rod mill customers in ROW deferred purchases in the final days of the quarter, waiting for copper to settle. As of this fiscal month ended October 28, copper prices closed at $3.70 a pound, which represents an increase of 17% from the end of the third quarter.