I'll try and answer your questions as best I can.
1) It will be hard to compare the two arrangements as first of all the DB plan bases the benefits on your final pensionable salary at retirement/leaving service. You wont know at the moment what this figure will be in most likelihood. Secondly, the DC benefits are based on future investment performance and the annuity rate at the time the benefits are been taken. There is no way to know either of these things.
In a nutshell, for DB schemes the investment risk is put on the employer, in a DC scheme you the employee take the investment risk. Its very unlikely that a change in the plan from DB to DC will benefit you.
2) Companies can change their pension scheme arrangements. They normally do this in consultation with employee's/unions. You could try to argue with your employer over this but if they are set on doing it, there is very little you can do about it.
3) Because you have 8 years scheme service, you have vested rights and cannot be forced to move your existing benefits you do you not wish to unless the scheme is totally wound up in which case you should get the amount that would have been needed to pay for your promised benefits. Bear in mind however that if there is a scheme short fall in funding then you may not get the benefits you have been promised under the scheme rules should the company fold and the scheme remains underfunded.
4) The process varies, sometimes employers allow existing DB scheme members to stay in the scheme and only allow new employees into a DC/PRSA arrangement. Sometimes they simply close the scheme period. Usually there is some correspondence to the employee as to what route they plan to take.
5) If you have outstanding queries about your contributions, you should address them in the first instance to the scheme administrator. If you fail to get satisfaction there then contact the scheme Trustee's as they are legally responsible for making sure the scheme runs properly. If you still have problems contact the Pensions Board/Pensions Ombudsman with your complaint.
6) In my opinion DB schemes are superior to DC schemes generally, each DB scheme can have different benefit structures however and maybe 1% of DC schemes may have better benefits than a substandard DB scheme if benefits promised are particularly poor. I have a large amount of experience with DB schemes and have yet to see a superior DC one however.
Ideally you would hope that only new employees will be put into a DC scheme and you would be allowed to remain where you are. If this isnt the case then you are best off seeking professional advice from an independent broker as there are many different factors such as the DB schemes benefit structure and long term viability of the company to get the schemes funding back on track to factor into any decision you make regarding transferring benefits or leaving them deferred in the scheme.
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