An and Ho's dates became widely used, but in 2015, Chinese palaeoanthropologist Zhu-Yu Zhu and colleagues noticed a discontinuity in the stratigraphy, which put the Chenchiawo mandible in Palaeosol Unit 6, and the Gongwangling skull all the way down in Palaeosol Unit 23. This makes them 1.65–1.59 million and 710–684 thousand years old.
The previously accepted dates for An and Ho's findings were challenged in 2015 when Zhu-Yu Zhu and colleagues discovered a discrepancy in the layering, which repositioned the Chenchiawo mandible to Palaeosol Unit 6, and the Gongwangling skull to Palaeosol Unit 23. This led to revised age estimates of 1.65–1.59 million and 710–684 thousand years.