Does the after snapshot script apply even if adding one article? 
I use this script to add one article at a time without having to snapshot again for all articles. 
execsp_changepublication @publication=N'PublicationName' ,@property=N'allow_anonymous' , @value='false'; 
go 
execsp_changepublication @publication=N'PublicationName' ,@property=N'immediate_sync' , @value='false'; 
go