SD.s calculations doesn't add up...

...in this article from DN today http://www.dn.se/nyheter/valet2010/sds-ekvation-gar-inte-ihop-1.1172182 the writer touches upon the subject on work migration to cover for the diminishing workforce, and the flaws in the politics of Sverigedemokraterna. They overestimate the costs of immigration and they underestimate the tax incomes from the working immigrants.