Hi,

>> z - s - 1000/100xp  (1:100 for example) but now that same factor doesn't work.

Yes ... this is depend on your current drawing items unit . i mean if it in ( m ,cm or mm ) .

>> 1000/100xp works with cm but not for mt nor mm ?

i suggest to check your current VP rectangle . check if it's as the same model layout units . 

Q: what do you mean by '' Scale list'' in your title :  Autocad for Mac Edit Scale List ?