There are ten (10) supplement insurance plans standardized by the federal government. Each is labeled with a letter. Every plan with the same letter offers the same benefits, no matter what state it is offered in or by which insurance company. Massachusetts, Minnesota and Wisconsin have different plans. The level of coverage varies. There are standardized plans that cover most all your Medicare deductibles, co payments and coinsurance, while others leave some costs for you to pay on your own. Medicare supplement plans provide nationwide coverage.