Order jumping around

<?php previous_post_link_plus( array(

                         'order_by' => 'post_name',

			 'order_2nd' => 'post_date',

                         'loop' => false,

                         'max_length' => 30,

                         'tooltip' => 'Previous episode',

                         'in_same_cat' => true,

                    ) );?> |

<?php next_post_link_plus( array(

                         'order_by' => 'post_name',

			 'order_2nd' => 'post_date',

                         'loop' => false,

                         'max_length' => 30,

                         'tooltip' => 'Next episode',

                         'in_same_cat' => true,	

                    ) );?>

I’m using the code above to order my posts.

My problem is that when I post up more than 10 videos, in order, it the link order seems to jump around.

For example here is Episode 1. It then jumps to Episode 10, and ignores all the others in between.

They are all in the same category, and only in one category so I can’t pinpoint the problem.

http://ww.wp.xz.cn/extend/plugins/ambrosite-nextprevious-post-link-plus/