My guess is the NetSuite's Freemarker configuration knows ${record.item.amount} is a currency field and automatically formats it. You're probably passing a number in your JSON object (as opposed to a string), which will drop any trailing zeros. If you want it to control the display from your JSON object, pass a string (see https://mdn.io/number/tofixed). If you want to control the display in using freemarker, try the string formatting directives (see https://freemarker.apache.org/docs/ref_builtins_number.html#ref_builtin_string_for_number)