Beginning with Drive Setup 1.7, the low level format option for all ATA drives has been disabled. This test was not performing a low level format. This test instead wrote zeros and performed subsequent reads to verify drive calculated checksums on the written data. With the exception of the read portion, this test was the same as the write zeroes option. The combination of both tests and the larger capacity drives that Apple is shipping provides unnecessary redundancy at the expense of the user experience.
Drive Setup users can achieve the same functionality by selecting the "Zero all data" initialization option before initializing the hard drive followed by the Test Disk... function in the Function menu.