Re: Question on Medicare co-insurance
I work in a medical billing office and we have a lot of patients that come in with Medicare and a supplement insurance. For most places, as long as they take Medicare, they will take your supplement/secondary insurance. The way Medicare works, is when they receive the claim from your health care provider, they automatically foward any remaining balance to whatever secondary insurance that you have on file (so it is important to let Medicare know all the necessary information about your secondary insurance).
HMO and PPO are types of managed care plans. Generally with a PPO, you have a larger network or providers to choose from and services do not have to be referred by a doctor. HMO usually requires that you select a primary care physician and all your services be referred by that provider. The network is not as big, but the cost is usually lower.
As far as the type of insurance to get, that is kind of up to you to decide. It really depends on your medical needs. If you are only getting part A Medicare, then a supplemental policy should work, because as long as you get the right plan, they will pick up any deductible and/or coinsurance. If you are getting both part A and B a supplemental will work as well for the same reason. A secondary will also work, but it is very important to understand your medical policy and how the plan pays out as secondary coverage.
There are times when you may need to see a specialist and that doctor may not take Medicare, well, that is when it is good to have a secondary insurance because, they will usually provide benefits for what is not covered by Medicare. Most supplement insurance only follow Medicare guidelines, and if Medicare pays or denies, then they will pay or deny.
The Medicare Replacement Plans are good as well. Most usually have just a copay. My grandmother uses one of those policies. I suggest looking into the options for the different policies and picking what is best for you financially and what will meet your needs medically.