In client script, I'm setting rate and amount in PostSourcing entry point but they are not changing. I changed Price Level to Custom and it works.

curRec.setCurrentSublistValue({
                            sublistId: "item",
                            fieldId: "price",
                            value: -1
                        });
                        curRec.setCurrentSublistValue({
                            sublistId: "item",
                            fieldId: "rate",
                            value: 5
                        });
                        curRec.setCurrentSublistValue({
                            sublistId: "item",
                            fieldId: "amount",
                            value: 10
                        });

But the rate and amount didn't change. Is there any something I did wrong?

setCurrentSublistValue is actually asynchronous, the price level, rate and amount arent actually set when the code runs