(AP Photo/Eduardo Verdugo)

Consumers and benefits advisors who look carefully may be able to find surprising Medicare supplement insurance bargains, a rating agency says.

Analysts at Weiss Ratings L.L.C., Jupiter, Fla. – a scrappy, independent rating agency – have come to that conclusion in a review of the Medigap rates that 165 insurers offered in 2011.

Medigap is a type of product that Medicare enrollees can use to fill in the deductible and co-payment gaps in Medicare Part A, which covers hospitalization, and Medicare Part B, which covers physician services and outpatient care.

Medicare plan open enrollment starts Saturday, and Weiss wants to use its Medigap rate database to sell individualized Medigap price reports to consumers.

Congress tried to bring order to the Medigap market in 1992 by creating 10 different standardized plan designs labeled A through N – just as Congress now is trying to bring order to the conventional health insurance market by establishing standardized gold, silver, bronze and bare-bones plan types for the health plans that are supposed to be sold through the new health insurance distribution exchanges starting in 2014.

Congress created the standardized plan types in an effort to discourage insurers from trying to undercut competitors or luring away healthier consumers by watering down plan designs or cutting out benefits of special interest to people with chronic health problems.

In the Medigap market, standardization of plan designs has not led to obvious standardization of product prices, or of value, Weiss reported Monday.

Weiss analysts have found that, across the nation, one plan may cost 13 times as much as another plan of the same type.

For Medigap Plan A, for example, the annual premium for a 65-year-old male could range from $439 to $5,776.

Some of the differences are due to geographic variations, but prices also can vary widely within the same ZIP code.

For a 65-year-old woman who lives in Kansas City, Mo., the annual premium for Plan A could vary from $830 to $3,074, and the annual premium for Plan F with a high deductible could vary from $428 to $1,199.

“We find that there is no justification for such wide price differences for exactly the same product in the same area,” Gavin Magor, a Weiss analyst, said in a statement about the Medigap rate review. “Consumers who research their options are likely to find opportunities for significant cost savings when purchasing Medigap insurance.”