marketpress adding .html extension to product

I managed to add taxonomy category to product url
making to show
localhost/products/office/table/product
through the help of this url
wordpress.stackexchange.com/questions/39500/how-to-create-a-permalink-structure-with-custom-taxonomies-and-custom-post-types

however i faced a problem with (sub-category/taxonomy)
meaning if i go to localhost/products/office/table
wordpress will tries to look for product “table” which in my case should be a subcategory hence a return of 404 page.

In my case, my category tree should look like this
there are 2 level category, with only one parent category and multiple subcategory and then product

• Office

• Chairs

• productA
• productB

• Table

• productC
• productD

• House

add_filter('rewrite_rules_array', 'mmp_rewrite_rules');
   function mmp_rewrite_rules($rules) {
    $newRules  = array();
    $newRules['products/(.+)/(.+)/?$'] = 'index.php?product=$matches[2]'; // my custom structure will always have the post name as the 5th uri segment
    //$newRules['products/(.+)/?$']                = 'index.php?product_category=$matches[1]';
	//$newRules['products/?$']                = 'index.php?product_category=$matches[0]';

    return array_merge($newRules, $rules);
}

i tried to add .html here
$newRules['products/(.+)/(.+)/?\.html$'] = 'index.php?product=$matches[2]';
and append .html to the filter_post_type_link filter function

the result is
subcategory work now, custom post type is added .html
but product failed to be queried.
when i switch the permalink setting back to default
i noticed the product page link became
localhost/?product=table.html
which is supposed to be
localhost/?product=table