Preset a download to variable pricing on post creation/save

default_enable_variable_pricing.php

/**
 * Preset a download to variable pricing on post creation/save
 *
 * @since 1.0
 */
add_action( 'save_post', 'beats_preset_variable_pricing', 20, 2 );
function beats_preset_variable_pricing( $post_id ) {
	// If this isn't a 'download' post, don't update it.
   	if( 'download' !== get_post_type() ) {
        return;
    }
    // Set variable pricing to true
    update_post_meta( $post_id, '_variable_pricing', true );

}