The body for UK universities is using “dodgy” figures during negotiations over changes to the Universities Superannuation Scheme (USS), a union has claimed.

Universities UK (UUK) is currently in negotiations with unions over changes to the £41.6bn (€50.3bn) USS that would see the UK’s largest pension fund close its final salary section and become a hybrid scheme.

However, the Universities and College Union (UCU) said the body was using “misleading” figures in its proposals that failed to account for USS members being promoted.

Citing work undertaken by the University of Oxford, the union’s head of bargaining Michael MacNeil said: “Modelling done for us and for others demonstrated that staff could see huge sums wiped off their pensions.

“We would be more than happy for further independent modelling to be done so USS members can be confident of the information being provided by the employers.”

The University of Oxford argued that UUK had failed to account for its staff’s career progression and expected incremental salary increases.

The university added: “We feel we should show our staff examples based on a realistic and typical career.”

The proposed changes, which have led to UCU balloting its members on strike action, would see pensionable pay for the career average section of the fund capped at either £40,000 or £50,000.

The final salary section, previously closed to new members but still open to accrual, would be closed, and all contributions above the defined benefit salary cap would be paid into a new defined contribution scheme.

In line with UK law, members would not see any changes to previously accrued benefits.

In other news, the UK has seen continued growth to private sector pension saving, as the rollout of auto-enrolment continues.

According to new figures released by the Department for Work & Pensions (DWP), 6.7m private sector workers were contributing to a pension fund in 2013, up from 5.9m in 2012.

The department also announced that nearly £78bn in contributions had flowed into public and private sector funds, up by more than £4bn from 2012, with nearly £40bn coming from private sector workers.

Commenting on the figures, pensions minister Steve Webb said: “Almost 7m people in the private sector are now saving, including many from low to middle-income occupations who have never had their own workplace pension before.

“And, surprisingly, it is young people who are the age group leading the way, with almost one in three of those in their 20s putting something by for their retirement.”

Lastly, the Pension Protection Fund (PPF) has released updated guidance for scheme valuation, meant in part to reflect changes to which schemes can be classed as money purchase.

The valuation guidance update also reflects the correct treatment of demographic hedging arrangements, such as longevity swaps.

The revised guidance – which also affects funds entering the lifeboat fund after sponsor insolvency or those seeking to re-enter if they were unable to secure benefits through buyout – can be found on the fund’s site.