Only the fields that are editable in the invoice's current status are applied. Fields that
are not editable are ignored without an error: the response is 200 and shows the unchanged
values, so compare the returned charge with what you sent.
While the invoice is draft, every field is editable. Once the invoice has been issued,
quantity, price_in_cents, name, and charge_item are ignored. description and
taxable are always applied. patient, practitioner, category, location, and date
are applied only while the charge's reporting period is unlocked.
price_in_cents is also ignored on a draft invoice when the charge carries a coverage
discount or is a package or prepaid item. Delete and re-create the charge to reprice it.