Question: I have read your tables for the partial low income subsidy deductibles and coinsurance. It refers to a $66 deductible and 15% coinsurance up to the threshold of $4750. Then $2.65 to $6.60 thereafter. Does the $66 deductible refer to the deductible for my prescription drug plan? Or is it a separate deductible that applies to the amount the subsidy pays? If I switched to a different prescription drug plan that has no deductible, would I immediately begin paying $2.65 to $6.60 instead of the 15%? I ask this because the insulin I take is $2494 for a 90 day supply. 15% is still a lot for me to pay. 

See table here: https://q1medicare.com/PartD-The-2013-Medicare-Part-D-Outlook.php#FPL150.

Answer:  Based on your question, I assume you are referring to the LIS partial subsidy benefit for people with an income between 136% to 150% of the federal poverty level and who have financial resources between $6,941-$11,570 (individuals) or $10,411-$23,120 (couples) .
 
The $66 deductible applies to your prescription drug coverage.  This means that you would be responsible for 100% of the first $66 of your drug costs.  After the $66 is met, you would pay 15% of your drug costs until you reach the maximum out-of-pocket threshold of $4,750 as you noted in your email.  For example, your first purchase of your 90-supply of insulin would cost you $430.20.  Here is the calculation: ($66 + (($2494-$66) x 15% )), which is (66 + (2428 x 15%)), or (66 + 364.20).  Your second purchase would simply be $2494 x 15% or $373.80.  These are rough estimates, because each plan can be different as to whether or not dispensing fees are included in the coinsurance. 

If you were to switch to a plan that has no deductible, you would jump over the deductible phase and go right into the coinsurance phase of 15%.  You would not reach the catastrophic phase ($2.65 to $6.60) until your total out-of-pocket costs have reached $4,750.

Also, if you were to switch plans mid-year, the deductible and coinsurance that you have paid thus far would follow you to the new plan.  So if your new plan has no deductible, the $66 deductible that you already paid on your current plan would still be applied to your out-of-pocket costs.

Related Links:
»  2013 Full LIS Benefit Parameters
» 2013 Partial LIS Benefit Parameters - For People Eligible for QMB/SLMB/QI, SSI or Applied
   and income at or below 135% FPL and resources < $6,940 (individuals) or < $10,410
»  2013 State Low-Income Subsidy Premium Benchmark Amounts (includes 2013 through 2006 for comparison)
» The 2014 Medicare Part D CMS Standard Benefit Model Plan Parameters
» Medicaid, Low-Income Subsidy (LIS) and Extra Help Articles
» Financial "Extra Help" Resources
» 2013 Non-LIS Benefit Parameters