as all POS systems are different, might not provide an API or if so have their own non-generic API implementation , no plans exist at the moment to integrate a generically usable integration of the plugin with any POS system.

However, there should be plenty of action hooks and code snippets (see https://www.wp-pizza.com/forum/code-snippets/) available that would let you program something for your particular system which would allow you to hook into the plugin as required