Two policies with the same standardised letter cover exactly the same things, so the only ways they can differ are price, service, and the rule by which the price changes over time. That last one is the rating method, it is decided by the insurer within whatever the state allows, and it is the part of a Medigap decision that behaves least like people expect.
The three methods
Attained age rating sets the premium by your age now, so it rises as you get older as well as with general increases. Issue age rating sets it by your age when the policy started, so it does not rise because you aged, though it can still rise for other reasons. Community rating charges everybody the same regardless of age. All three are lawful, which is available depends on the state, and the same insurer may use different methods in different states.
Why the cheapest quote can be the expensive one
An attained age policy is typically the cheapest at sixty-five and the most expensive later, because the price is tied to the thing that only moves one way. Comparing two premiums at the moment of purchase therefore compares the wrong thing: the comparison that matters runs over the decades the policy is meant to cover. That is an arithmetic problem, and it is a good reason to ask the method before asking the price.
Where it is disclosed, and what this site will not do
The rating method is disclosed in the policy documents and the outline of coverage, and state insurance departments publish guidance on what is permitted locally. This site quotes no Medigap premium, because no insurer publishes one without underwriting an individual, and an average premium is a figure nobody is charged. What it publishes instead is how many people in each state kept Original Medicare, which is the population a supplement sits behind.
Questions people ask about attained age vs issue age
Which rating method is best?
There is no general answer. It depends on how long the policy is held and what happens to premiums, and this site makes no recommendation.
Can an issue age policy still go up?
Yes. It does not rise because you aged, but it can rise for other reasons the policy allows.
How do I find out the method?
It is in the policy documents and the outline of coverage. Your state insurance department publishes what is permitted locally.
Does this site show Medigap prices?
No. They are not published anywhere in a form that would be true of a reader, so quoting one would be inventing it.