Pensions experts say even they do not fully understand all the extra charges, which are buried in the complicated fine print of contracts their clients are being asked to sign.
The extra charges levied by some companies, including Scottish Equitable, Skandia Life, Abbey Life, Sun Life and Albany Life, do not show up in the headline figures designed by the Personal Investment Authority, the financial regulator, to help consumers. Policyholders risk paying thousands of pounds in extra fees depending on the scale of their contributions. Those facing the heaviest penalties are the majority of policyholders who halt their pensions payments.
Details of the charges follow a new investigation into personal pensions by the Office of Fair Trading and appear in Money Marketing, the specialist financial newspaper.
The extra fees levied by Scottish Equitable, which takes more than pounds 30m a month in pensions premiums, are called the "specific member charge", where contributions are halted or reduced during the lifetime of a policy. Yet Scottish Equitable admits that unemployment, divorce and the offer of company pension schemes force eight per cent of its policyholders to stop their payments every year. Hundreds more reduce the amount they pay in. After 10 years, the majority of the company's holders of monthly premium pensions are likely to have stopped contributing - and will therefore pay higher charges even when no money is going in.
Scottish Equitable also raises the percentage it takes out of a contract when policyholders raise contributions, despite - or perhaps because of - insurers' exhortations to do just that.
Skandia Life also raises charges for policyholders who reduce or stop their payments by means of a "contribution servicing charge". A policyholder who pays pounds 50 a month into a 25-year policy with Skandia and misses the third year's payments will pay an extra pounds 68 as a penalty for missing contributions.
With the pounds 2.45 a month that is charged just for having the pension scheme, this adds up to a charge of pounds 97 for a pension plan into which no money is going. Skandia will not repay the charge - even if the policyholder resumes payment and repays all of the necessary contributions.
Abbey Life, owned by Lloyds Bank, charges an extra six per cent of a fund if the pension is halted within a year of starting, reducing to one per cent in year six.
Sun Life improves its annual premium pensions by boosting policyholders' funds by an extra 2.5 per cent every month. However, the extra cash injection only happens over about 36 months, between about eight and five years before retirement.
While Sun Life is able to show improved terms on its 25-year pensions by this "extra fund injection", the vast majority of scheme members who are forced to stop payments early pay through the nose. The company said this week it is reviewing its policy.
A similar policy is adopted by Albany Life, owned by US insurance giant Metropolitan Life, which pays a "loyalty bonus" ranging between two per cent in years 10 to 13 of a unit-linked pension, up to 10 per cent after 25 years. This too has the convenient effect of improving Albany's projected charges. But for the majority of its policyholders to benefit from the new charges, the company's lapse rates would have to be several times lower than industry averages.
The charges cast doubt on the validity of key reforms introduced by the Personal Investment Authority, supposedly to help consumers measure the cost of a personal pension contract. But the key figures apply only if payments are kept up at the same level to retirement. Earlier this year the Independent revealed that despite claims that its reforms were working, company charges were actually going up.
According to actuarial consultancy AKG, fewer than 35 per cent of premiums to personal pensions are still being paid after 10 years. Most last no longer than six years.
Nick Bamford, managing director of pension specialists Informed Choice, said: "I inherited a client with a regular ScotEq personal pension and we tried to work out how much he'd pay if he had a career break. We asked for a table to help work it out but ScotEq wouldn't give us that. I read the charging structure 12 times before I had even a vague idea of how it worked."
Graham Dumble, head of marketing at Scottish Equitable, says: "It is certainly not designed to exploit the weaknesses of the disclosure regime. We do not sell on price alone. All we have done is to tailor the charge to people's circumstances."
Skandia Life often appears at the top of league tables designed to help advisers decide who gives the best value. The company's pensions marketing manager, Peter Jordan, admits that few are likely to maintain level contributions throughout the contract.
"We don't have the luxury of high charges at the start of the contract, so we make use of this to cover our costs. But there are very few who pay commission up-front who do not impose penalties," he said.
Skandia adds that it has been reviewing its contribution servicing charge since before the Office of Fair Trading announced it would investigate personal pensions.