The estimated bill for payments to former police officers injured on duty is now £613m - 26% higher than when the Audit Office called for action.
The increase - of £124m - is revealed after a report by the spending watchdog in March said the scheme is "not fit for purpose".
The Department of Justice (DoJ) aims to cut the cost by amending legislation.
The PSNI said the estimated costs are "subject to a number of assumptions that can fluctuate year to year".
SDLP Policing Board member Dolores Kelly said the issue should have been addressed long ago.
"The department didn't have much choice but to act, but this was known about for years and should not have taken an Audit Office report," she said.
"Firefighters and other first responders do not get anything like this, nor will those who are suffering an obscene delay waiting on the troubles pension."
Figures given to BBC News NI in a Freedom of Information request are more up-to-date than those contained in the Audit Office report.
It had said the Police Service of Northern Ireland (PSNI) was facing future payments, or liabilities, of £488m over the scheme's lifetime.
However, a year later a new calculation puts the figure at £613m.
In total, 3,000 former officers are now receiving monthly amounts for life, on top of one-off awards which can be backdated several years.
The PSNI said changes to the scheme being planned by the DoJ would "ensure the most effective approach" in providing for officers "whilst demonstrating an appropriate use of public money".
Applications have soared since 2015, with many linked to post-traumatic stress disorder.
Medical assessments in support of the applications cost the DoJ and the Northern Ireland Policing Board £228,000 last year alone.
Figures also reveal that almost 50% of rejected applications get overturned on appeal.
Mark Lindsay, the chairman of the Police Federation, which represents serving officers, said the payments should be seen as compensation.
"This should not be about figures but what policing in Northern Ireland has done to officers."
He added that "there is something not right" about an assessment process which sees so many rejected applications overturned on appeal.
The Policing Board said it has drawn the issue to the department's attention.
The board, the DoJ and the PSNI have formed a working group following the Audit Office report to act on its recommendations.
The department said it is planning to make changes to legislation "to ensure injury on duty awards are reduced".