[Koha] link_bibs_to_authorities problem

[Erlanda Simonyan]

Dear List, 

We imported a butch of bibs & a butch of authorities from koha 3.18.05 to koha 17.05,
after using link_bibs_to_authorities.pl we have got such results

Number of bibs checked:                 5817
Number of bibs modified:                5701
Number of headings linked:              8406
Number of headings unlinked:            24019
Number of headings fuzzily linked:      0


 BUT it  isn't link correctly all headings,   all authorities with the same "surname" but other "name"  were linked together.(EX.: Abrahamyan Suren , Abrahamyan  Armen, Abrahamyan Karen link to Abrahamyan Suren)
So koha find  only" Surname" for matching and  link them.
Pls help to solve this problem.
Thanks,
Erlanda