When Pricelists are enabled/created in Zoho Books, we are not able to restrict users from changing the default ones defined for a single or group of Customers.
The use case is as follows: A business has a standard set of price list defined for a group of customers. This is created and associated to each customer in Customer record. When a user create a Sales Order/Invoice for this customer, the associated price list is selected as default in the price list dropdown but the system also allows the users to override the selection by letting users choose from the other price lists that are setup in the system. This breaks the control that the business would like to have and creates issues. Similar to how there are permissions for users that controls them changing the selling price of an item in Sales Order/Invoice, there should be controls available in the system for users that can restrict certain users from changing the pre-defined price list for a customer. This will bring in better control.