Being confused with how the author describe the time frame

Dasgupta,2019,p.2597 said that

the treated group comprises all firms that are headquartered in
countries that have passed a leniency law by year t. The control
group comprises firms in countries that never adopted a
leniency law in our sample period and firms headquartered in countries
that adopted a leniency law at some later point of time.

Whether the control group includes firms in countries that implemented this law at some earlier point in time? My understanding is: for example, from Table 2, Dasgupta,2019, page 2599, Korea passed the laws in 1997, therefore, the control group including all firms in all countries not implemented this law from 1995 to 2002, including the US.
From my point of view, it should be the case because base on this identification, firms in the US will not be affected by the laws passed in Korea based on this identification so these US firms from 1995-1996 and 1998-2002 can be control observations for Korea.

But if it is the case, why they need to write down "adopted a leniency law at some later point of time". Because in Korea case, the word "our sample period" means "1995-2002" already.