autoship_override_simple_frequency_options_default

(src > product-options.php) Allows you to override the default setting for the Overrode Defaults frequency option for both Simple products. Takes the current setting and the product or variation ids.

Example

// change custom default frequency of beer boot product # 2846
function xx_override_custom_frequencies ($override, $product_id){
    // return 'yes';
    return $product_id == 2846 ? 'yes' : $override;
}
add_filter('autoship_override_simple_frequency_options_default', 'xx_override_custom_frequencies', 10, 2);