Phppointofsale is an excellent POS system. But we need more functions integrated to it.
1. User can generate sales quotations.
2. User can convert quotations into and Job Order (Just a list detailing the jobs)
3. User can convert the quotations to invoices
4. Very Simple reports.
Implement these with as little page loads as possible. eg use AJAX
When a new version of phppointofsale is available, it should be upgradable with little changes to your code.
More details in the attached docs.