If you ever needed proof that simplicity isn't easy just read this discussion document released this week titled 'Periodic reporting regulations for retail KiwiSaver schemes'.

The aim of the document, according to a statement by Commerce Minister Simon Power, is to encourage submissions on ways "to make KiwiSaver easier to understand".

"If the 1.5 million people in KiwiSaver are to have confidence in the scheme then they need to be able to rely on the information they are given - and for that to happen the information needs to be easily compared across funds," Power said in his statement.

I know what he means. For the last three years I've been compiling data culled from the annual reports of 40 or so KiwiSaver schemes and even in these documents, which theoretically should be the most consistent of all, there's a remarkable degree of diversity.

As Power's discussion document discusses at length, the most confusing, and controversial, aspect of KiwiSaver scheme reporting is how they account for fees and expenses. I have certainly noticed huge variations in the KiwiSaver fees and expenses reporting methods.

Nonetheless, I have been able to extract a joint fee/expense figure for each KiwiSaver scheme, which, imperfect as it may be, represents a rough overall cost to members.

In my scale, for the year to March 31, 2010, KiwiSaver costs per member ranged from about $35 for the ANZ scheme to just over $255 for the NZ Harbours scheme. I haven't graphed it all but the results would no doubt take on the classic bell-curve shape familiar to statisticians.

As you'd expect, the larger schemes are generally cheaper, on a per-member basis, than smaller ones - economies of scale etc - but it doesn't always hold true.

According to my research, of the KiwiSaver schemes with more than 10,000 members, Fisher Funds - at an annual cost of about $123 per member - was by far the most expensive.

I reported Fisher KiwiSaver costs of about $1.97 million over the year and it would've been even higher until Glenn Ashwell, general manager of the scheme, pointed out to me that a performance fee reported in the annual accounts included a $434,000 amount that they "never received and never will" (ask an accountant, something to do with 'accrual').

Ashwell also makes the valid argument that it's "very important that if fees are being quoted then returns are also presented" and Fisher (48.88 per cent for its growth fund) did have a good year.

Cost is one thing, value is another and it's possible that some of the changes to KiwiSaver reporting rules mooted in the latest discussion document will help members determine both.

As well as the quantitative stuff, I liked the proposals requiring all KiwiSaver schemes to report quarterly on what they have actually invested in. Currently, there's a pretty ad hoc approach to reporting on asset location, which does need to be made consistent across all schemes.

If you do bother to read annual reports, though, you can still discover some interesting facts. Here's a few teasers from the most recent batch:

The Huljich scheme now invests into the Australian-based Platinum International fund rather than trying to manage global equities from Auckland itself;

Mercer fired four underlying managers and hired three new ones in the year to March 31;

The PSBG scheme had invested $328,905, or 38 per cent of its total assets, in unnamed debentures;

The Anglican Koinonia scheme has taken KiwiSaver into the green age with the inaugural inclusion of carbon credits in its asset valuation. As at March 31 this year, the Anglican KiwiSavers had "594 carbon credits on hand... which have been valued at $10 per tonne".

It's simple really.