Chung is out of top 100, he's been in freefall this year. Kind of looked promising when he made the triple TB against Wawrinka at USO, but he's in some serious trouble now.
Not sure if freefall is the right word for Chung, more of an expected regression. If he achieved his high ranking and all those ATP entries by actual big match wins it would've been one thing, but it was mostly thru low tier(player field-wise) Asian Challengers. Players taking "good losses" to top players are aplenty, but is not a good indicator for the rankings.
I mean, I'm not sure if Chung beat more top100 players than your average challenger player last year. After half a season this year, he has three such wins. It will be better for him to be ranked appropriately and work on his game in a winnable environment. Was clearly overranked around the 50-60 mark, whether that was still impressive considering his age is another matter.