The fact is, most states’ sales tax codes are ambiguously written for good reasons, the codes create a lack of certainty on the tax-ability of an item. A legislative body decides it needs revenue and drafts a bill to that effect, however, sometimes legislature creates incentives for companies to move into their state; to create more jobs, which creates more spending. Those incentives are where STS comes into the playing field, and where the opportunities exist.
The opportunity to recover sales and use taxes that your company has already paid passes as every statute of limitations expires. Letting the next statute run out could translate into thousands of dollars you will never be able to get back.