Technology blog Asymco has won plaudits for its deep dives into data from Apple and other mobile industry companies, but its latest post looks flawed. Analyst Horace Dediu digs into Apple’s financial data and recently-announced iTunes milestones – 400m iTunes accounts and 365m iOS devices sold – calculating that with original iPods factored in, Apple has sold 680m mobile devices in the last decade. Cross-referencing that against iTunes accounts leads him to believe that “about 60% of all Apple’s devices sold are still in use”. The problem? “If we assume that account holders typically use one device…” We suspect that the actual ratio is significantly higher, as do a number of commenters on the post itself.