about choosing saddle width

today I went to LBS to measure my sit bone width,the fitter use shimano sit bone tools to measure my sit bone width is 13cm.
I want to buy selleitlia ,ulr below
https://www.selleitalia.com/en/saddl...nio-superflow/
size s3 width is 130mm
size l3 width is 146mm
according to https://www.selleitalia.com/en/idmatch-experience/
idmatch,I go through 7 steps ,the result size is s3 but which only 130 width.
is it all right for me ? s3?
according to youtube or google I should choose my sit bone width plus 20mm which should be 150.
so how can I choose?
7 steps is below
1 male
2 height 179
3 body size medium
4 medium flexible
5 what kind of biker : road
6 which is your target : Medio fondo（sometimes I ride at night for 20km ,so I choose this one） Granfondo (sunday or sartaday I sometimes ride about 60-100km)Endurance(I don't understand this type) Cycle-Touring(I don't understand this type)
7 how long have you ride :I choose >6hours
the result size is s3 ,SP-01 BOOST KIT CARBONIO SUPERFLOW https://www.selleitalia.com/en/saddl...o-superflow-s/

so ,what the best choice for me?
I have called selleitalia about my question,the tech man told me should follow idmatch.......I also told him my sit bone width is 13cm.
my english is not good,can't fully understand he told me ,but his advice is s3 based on idmatch.



https://www.mantel.com/uk/selle-ital...perflow-saddle

seat bone width 115-129 s3 130-144 l3,so how can I choose?