This would vary considerably from state to state.
One of the main ways that a small estates procedure will usually differ from a normal probate estate process is the way that creditor's claims are handled. Typically, a small estate threshold is set up so that all assets in qualifying estates are exempt from creditor's claims. If the threshold is exceeded, the process of giving notice to creditors and processing creditors claims must usually be initiated.
Sometimes, a small estate threshold is also set in a manner that causes all inheritances to be distributed to a spouse and/or minor children in lieu of personal designated in an intestacy statute or pursuant to the language of a will, due to statutory preferences for those persons. In those cases, the process of determining the validity of a will is dispensed with in a small estate, but must be determined when those statutory priority payment thresholds have been exhausted.
But, it is hard to make general statements. There is more interstate diversity in probate procedure than in most areas of U.S. state law, and small estate processes are equally diverse.