How to Account for Advance payment to a Client without Invoicing

How to Account for Advance payment to a Client without Invoicing

In the Health Care Industry particularly in the Capital Equipment purchased by Hospitals we follow a certain format for payment collection
1. Quote is generated for the customer.
2. PO is release on behalf of the company 
3. Payment terms are 60% as advance 20% when it reaches customs and after customer clearance the equipment get repacked at our ware house and then Eway bill is generated and invoice is raised on behalf of the Hospital. once it reaches the Hospital site 10% is collected and then upon erection 10% is collected.
4. Now in this scenario how can i track pending payment from customer even before invoice is raised.
Is it possible in Zoho to know the balance due from Hospital end.