Options +FollowSymLinks
RewriteEngine on
RewriteBase /
# force tailing slash for all urls starting with /outbound/
RewriteRule ^outbound/.*[^/]$ /$0/ [R=301,L]
#remove tailing slash for all except urls starting with /outbound/
RewriteCond $1 !^outbound/
RewriteRule ^(.+)/$ /$1 [R=301,L]
RewriteRule ^pa/?$ /admin/index.php [L,QSA]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^outbound/([^/]*)/([^/]*)/$ /outbound.php?type=$1&id=$2 [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^/]+)$ stores.php?store=$1 [L]
I also cleaned it up a bit.