ORA-00059: maximum number of DB_FILES exceeded

ORA-00059:maximum number of DB_FILES exceeded
Oracle10g(10.2.0.1.0)

I would like to add some data files, but the max number of db_files exceeded.
My plan of changing this parameter is following 1-11.

I was going to change the parameter of db_files on "init.ora".
I made PFILE(init.ora) from SPFILE,
but there isn't "*.db_files=200" on init.ora.

Is there any problem?
How should I change the parameter of db_files?

Also, now the number of db_files is 170,
and the db_files parameter is 200 (default),
and the maxdatafiles is also 200.
Should I change the maxdatafiles too?