7zip with date range .vs. filelist created with dir and daterange

#1
Running 7zp with a DIR created filelist with a daterange is a lot faster the 7zip and date range. Is this works as intended?

1a) dir /[2016-01-01,2017-03-03] >datelist.lst
1b) 7zip [...] @datelist.lst

2) 7zip /[2016-01-01,2017-03-03] [...]

Why would 1a+b be faster then just 2?