While this is important info for estimating the sustainability of cryonics orgs (reducing benefits in the cost-benefit analysis), I don't think it shows that cost estimates are wrong: membership fees are on an annual basis, and can be terminated if you decide to stop using the service, and the life insurance proceeds can be reallocated from cryonics to other applications if you terminate membership. I.e. as estimates of the cost of a few years' cryonics insurance to an individual today, current estimates are right. As estimates of lifetime expenditures if one wants cryonics protection no matter how expensive it becomes, they are too low.
One of the sticking points for cryonics is how expensive it is. Unfortunately, the estimates on LW (eg. in Normal Cryonics) are likely to be low as they are current costs. This is starting to come to a head for Alcor, with Alcor's low growth rate meaning it faces a rising tide of aging members (hence that emphasis on young cryonicists) and fundamental flaws in its prices; the official word has come down in the latest issue of Cryonics, issue 2011 q4:
Cryopreservation Funding and Inflation: The need for Action; A Discussion Article by the Management and Board of Directors of Alcor
What to do?
Hope the old grandfathered members like Mike Darwin (who predicted this, in the February and March 1988 issues of Cryonics) can afford that.
On a parting note, I read somewhere that CI's low prices have rarely risen. I wonder what their projections look like...