Error when adding product to cart

I am using the Flexible Shipping plugin together with WOOCS. Everything was ok up until about 10+ days ago when adding a product to cart results in a “critical error” with the following line:

Uncaught Error: Call to a member function woocs_exchange_value() on bool in /var/www/vhosts/(website url)/httpdocs/wp-content/plugins/flexible-shipping/classes/table-rate/multicurrency.php:112

I checked the folder and below is what I see for Line 111 and 112:

public function flexible_shipping_value_in_currency_woocs( $value ) {
return $GLOBALS[‘WOOCS’]->woocs_exchange_value( $value );

The error disappears when I deactivate WOOCS.

I have also reached out to Flexible Shipping for support, but in the meantime would like to know if I can get some insight as to what is happening here.

Thanks!