Interpretation of the law determines whether there is any retroactive changes to the law being made.
If retroactively changing the law, it may be unconstitutional.
If the interpretation is simply incorrect, then no change in the law is being suggested, the interpretation is only being corrected (changed).
However, then the interpretation could be considered to being changed retroactively.
Does it matter if the law is changed or the interpretation is changed?
The answer likely depends on who is making the change.
The issues:
What is the law?
What is the correct interpretation of the law?
What is the basis of that interpretation?
Will the courts agree?
State tax laws are challenged because either the state has made an assessment and believes additional tax is due based on the state's interpretation of the law.
But what if the law is vague or ambiguous, open to interpretation?
What if the company has a different interpretation of the law?
Who wins?
Deference. What is it?
Judicial deference is the idea that under some circumstances, a court should defer to a state agency's interpretation of a statute or regulation rather than the court imposing its own interpretation.
Recently the U.S. Supreme court ruled in Loper Bright Enterprises v. Raimondo which overturned the Chevron doctrine. The Chevron doctrine gave deference to the state agency's interpretation.
From a state perspective, several states did not follow the Chevron doctrine. Some states even have anti-deference statutes.
Georgia codified antideference in 2021 specifically for tax matters providing that all quesitons of law to be decided by a court or the Georgia Tax Tribunal are to be made "without any deference to any determination or interpretation, writen or unwritten, that may have been made on the matter."
Tennessee amended its statutes effective April 2022 providing that when interpreting a state statute or rule, a court should not give deference to a state agency's interpretation and should interpret the statute "de novo."
CONCLUSION
Interpretation matters.
Public knowledge of the state's interpretation is necessary if we are to have any level of certainty and compliance.
Public knowledge of the state's interpretation allows companies to make determinations as to whether they agree with that interpretation and either accept it or challenge it.
Retroactively changing the law or the interpretation of the law can have adverse effects on not only the taxpayer involved, but the taxpayer community at large.
Ambiguity in a law creates confusion, different interpretations, risk, opportunity and ultimately, most likely, litigation.
Stay sharp. Be safe.