Surely a 3 year 'trial' is flawed if, as you say, it is there to encouage those approaching their 12 year point to stay on? If the FRI is given at the 17 year point and is on 'trial' for a 3 year period then only those at 14 years service or more will benefit, therefore the trial does not actually consider those for who you say the FRI is aimed at
How about a retention bonus at the IPP to keep those in that would otherwise be lured away by their gratuity?
MadMark!!!