I would argue that Zhang was under-ranked the whole time.
When she entered the UFC and got her first win she should have gone straight into the rankings based on her record.
The people doing the rankings do not know WMMA, hell, they had people ranked at bantamweight who had been cut two years ago. They only recently ranked Gillian Robertson after four straight wins at 125, but had Maycee Barber ranked at 125...
Weili should have slotted in somewhere inside the top 12 the minute she won her first UFC fight just based on her record.
(another one is Xiaonan Yan - she should be ranked but isnt. Just ignorance on the part of the so called media that do the rankings)