I learnt today about the "theme_hook_suggestion" (without the trailing "s") variable in templates: it bypasses any other suggestions that even the theme sets. Of course, it's easy to unset() manually, but it's also much less known and people whose habbits are to always mess up with "theme_hook_suggestions" array (with the trailing "s") gets easily confused when they don't see their own suggestions being applied, even if they have a higher priority.
In includes/style.inc (arround line 380) you do:
// Set AF template as most significant suggestion
$variables['theme_hook_suggestion'] = $template;
$variables['theme_hook_suggestions'] = $template;
Which is both a duplicate and confusing for themers using your module; Especially when you have numerous view modes and different templates for those view modes, because your own will always bypass every other, unless that like me, you do proceed to the
theme() function step debugging and find out about this subptile mysterious hack.
I suggest that you remove the "theme_hook_suggestion" from your templates considering that you already use the "theme_hook_suggestions" anyway, with higher priority than core.