Back what up? That those over 60 are going to pay substantially more? I don't need links. I've compared rates in a number of states from existing plans to ones offered through the exchanges. I did this to confirm complaints from many people over 60 who are caught in this trap. It is one of the downsides of the plans that are offered through the exchanges.
If you want to check it out for yourself though, you can just check out the subsidy calculator.
Subsidy Calculator | The Henry J. Kaiser Family Foundation
If you use my example, you will see the big flaw in the way the subsidies work. I used the state of Ohio. For a couple aged 63 and 61 respectively, the estimated cost for a silver plan is $13134 per year. At an income level of $62,000, which is exactly 400% of poverty level, this hypothetical couple would receive a tax credit of $7244, making them responsible for $5890 to cover their premiums. Not a bad deal, right? Now change their income to $63,000. If you did this correctly what you will see is that this couple no longer qualifies for a tax credit and now must pay the full $13134 per year for their insurance. Their income is only $1000 higher but they will now have to pay an additional $7244 for their insurance. These people are going to get hammered.
Now as you will see, this comes to almost 21% or their income, so they actually could go without insurance and not be penalized because the cost of the insurance is over 9.5% of their income, but at age 60 plus, going without insurance is really not a very wise option. What I really wish Republicans had done is addressed issues like this, and pushed for changes that would have had a positive affect on those who will need to use these exchanges to purchase their insurance. Instead, they wasted everyone's time by trying to stop the whole thing which was never going to happen.