Hi czechmate - You ask quite a few questions there. I will attempt to answer some.
In relation to the State Pension, Class A contributions are Class A contributions - it makes no difference whether they are "earned" in the public or private sector.
It looks like your friend has at least 11 years to go before reaching state pension age.The current contribution requirements for this pension are due to change around 2020 and the details of the new requirements have not been finalised yet. So it is not possible to say what level of pension she (?) will qualify for - or how precisely it will be calculated. Based on your info, it is likely to be less than a full pension. However, the more Class A contributions - or Class A Credits - she has the better, so she should aim to keep up her record after retirement.
For people with both Class A and Class D contributions there is currently a provision for the state pension to be calculated on a
pro-rata basis (some explanation here :
http://www.citizensinformation.ie/e...etired_people/state_pension_contributory.html ). Others would be able to explain this better than me. In any event the changes to come in the system will probably affect this also. All your friend can do is try to keep up her Class A record.
I don't know whether your friends may originally have been misclassified as Class A - I understand that it has happened. She should query this with the Department. Is she sure she was in the Pension Scheme during those years ? If not, she could "buy back" those years now - it is good value. In general your point above is correct - if it was all at Class D she should get a bigger pension now at 56 but could potentially be disadvantaged by missing out on the State Pension.
However, from your post above it seems that both her Class A and Class D service is already pensioned (and all in the one Pension Scheme?). I do know for sure that some retiring public servants have both Class A and Class D years. So that in itself is not that unusual. Working on this basis:
(1) If you friend retires at 56 she should qualify for an actuarially reduced pension based on both her coordinated Class A service and her uncoordinated Class D service.
(2) At 60 she can apply for a Supplementary Pension based on her coordinated Class A service. This should be granted provided she meets the conditions - one of which being that the applicant is not engaged in any paid employment or self-employment. If your friend intends to continue working after 60 then she would not qualify.
(3) State pension at 68 based on her total PRSI contributions and credits (currently pro rata combination of Classes A and D) - calculated according to criteria we are not currently sure about. Any Supplementary Pension in payment will stop at that stage (assuming that the level of Supplementary being paid is less than the level of Pension granted - very likely, but if not, she should get the excess).
As regards (2) above. Should your friend take early retirement at 56 and obtain employment with Class A PRSI, she should enhance her state pension prospects. Should this employment cease for some reason at 60 she could then apply for Unemployment Benefit. If she qualifies she would get Class A Credits while on the Benefit. If still unemployed at the end of Benefits, she could continue to sign for Class A Credits. Class A Credits also count towards the State Pension (up to certain limits). She could also apply for the Supplementary Pension based on her Class A Years (once she is not working or receiving a Social Welfare payment). As she has only about 6 pensionable years at Class A any Supplementary is likely to be a small amount.