Going from family coverage to individual and adult children covered

[Guest njdunning]

If someone makes their contribution to his HSA for 2014 for the full 6550 but only had family HDHP for 6 months, and then changes in 2015 from family to individual HDHP coverage, do they have to go back and recalculate what was eligible?

Also, is there something about the adult child who is on the parents HDHP being able to contribute to their own HSA? How does this affect the parents contribution amounts and can someone direct me to where this is written that it is allowed (if it is).

Thanks!