a confusion about @SSwarper

Dear AFNI gurus,

I am very happy to learn @SSwarper today, which I think is very useful to give us a clean brain.
I played this function immediately.
Interestingly, the anatSS file was not as good as the anatS file. Specially, the anatSS file was left with a slight border (residual skull) around the brain. The anatS file is perfect.
Although I think the anatQQ file is reasonably nice, it confuse me why the anatSS file do not look good as the anatS file.
Is it possible that the MNI_2009_template used to mask the brain is a little bigger than the anatomical image used? I used a young Chinese brain (20 yrs old)

I am very very sorry I might be a little neat freakā€¦