Dear list members,
1) Both Whitney and MacDonell and Coulson's sandhi chart say that word final "n" remains unchanged before "s".

But checking three different printed editions of the Daksinamurtistotram, they all have:
 अमुष्मिं स्तवे

What do the grammarians say about word final "n" before "s"?  Is it optional to change a word final "n" to anusvara before "s" or  Is the anusvara in this case merely a typographical convenience?  

Thanks,
Harry Spier