Hello Mitra Safari,
Odoo Point of Sale is fully integrated with the Inventory and Accounting applications. Any transaction in your point of sale will be automatically registered in your stock and accounting entries.While lunch module is very simple having their own products,categories & payment options and it is mainly designed to ordering meals for employees within company.
There is a third party module which allows to deduct lunch amount from employee salary: https://apps.odoo.com/apps/modules/12.0/lunch_payroll/
PoS mainly focuses on customers, when you want to deal with multiple customers at a time then PoS usage is best.
Session Control:
Configure Point of Sale and you can see all available sessions on PoS dashboard,start a new session.Note that multiple users can not access same session.It’s strongly advised to close your PoS session at the end of each day.Upon closing user can see a summary of all transactions happened within that session.
PoS Order Cancellation:
There is no way to cancel paid pos order, you can do refund by inserting negative values from POS screen.
So, I prefer you to use lunch module.
Regards,
Email: odoo@aktivsoftware.com
Skype: kalpeshmaheshwari