It says that it doesn't explain the "conundrum" of increased higher-end scores. But it definitely addresses that it's very unlikely the test has gotten easier, since average scores have remained stable, as they have for the PSAT and ACT.
If the top 20% of the population took the ACT in the 1980's and now its the top 60%, one could easily see how the test got easier and the average scores remained stable.
It says that it doesn't explain the "conundrum" of increased higher-end scores. But it definitely addresses that it's very unlikely the test has gotten easier, since average scores have remained stable, as they have for the PSAT and ACT.