Secondary Health Insurance

When you talk about the secondary insurance you usually think of covering the expenses that the primary insurance doesn't cover. This looks good specially when you have planned medical procedure or so as deductibles in the primary insurance can consume your budget very fast.
However on the other hand by emerging HDHP (High Deductible Health Plan) and their bonding to HSA there are some limitation in use of secondary insurance.
Lets review the 3 possibilities for primary and secondary insurances that I can think of:
1. both HSA base
Plans based on HSA, have usually high deductible and therefore the deductible amount should be paid by HSA account first and then insurance kicks in. So only after paying all the deductible, secondary insurance can cover the out of packets expenses left over from primary one which should not help that much. Moreover HSA is per family and can not go more than IRS limit.
2. both traditional base
This can help people with secondary insurance as the secondary one covers some or all of the out of pocket expenses that the primary insurance doesn't cover as if it was the primary one.
3. one HSA and one traditional base
This is not allowed for having secondary insurance and as far as I know the insurances do not let the clients to do that.

Cheers,
HTP