In the USA the NTEP program is recognized by all states, but the interpretation of which applications should use an NTEP scale varies from state to state. The big question is not if the law requires an NTEP scale, but rather, would the business benefit from from an NTEP scale.
Now consider buying a scale or balance cheaply. Whatever you buy or sell is calculated by that piece of equipment. If a business sells $300,000 a year worth of chicken legs and their scale is 1% out (in the customers favor), they lose $3,000 which is way more than saved by buying a cheap scale. Consider the scale or balance to be a cash register. It counts money for the business owner!
Buying an NTEP scale or balance is a protection against poorly manufactured equipment. NTEP scales go through a rigorous set of tests that not only take months, but also cost a great deal. They check to see if the weighing device stays accurate when the temperature changes over time and to ensure the scale will take a lot of abuse, and most importantly, the customer gets the correct result.