Its important to note that a reciprocal agreement entitles you only to apply for benefits. Whether benefits are paid depends on other criteria. Not all residents are eligible for all benefits.
Benefits are paid at a flat rate, irrespective of your previous income. They are taxable (assuming you earn enough to pay tax) and the Department of Social Welfare deducts the tax due before paying benefits. If you receive a benefit for the first time and aren't registered for tax, you should contact your local Inland Revenue Department, or IRD office.