Is it normal for your PRSI deduction to increase or decrease from month to month?
Mine has just decreased this month for some reason, but no salary change or anything. Is this normal or do I need to go and check it out with the Payroll people in my company?
Did you just hit the threshold for the year (€38k iirc)? Unlike PAYE, PRSI is not spread evenly across the year. You pay full PRSI until you hit the threshold. Once you've hit the threshold, you just pay the 2% levies.