Half life of 16 hours does not fucking mean that the metabolites of that drug are completely excreted from the body in 16 hours. It means that the active component of the drug is reduced by 50% in 16 hours.
Steroids cause organic growth of tissues in body, metabolites can get retained in fat cells and they depend upon number of factors, such as, age, metabolism, tolerance, physical illnesses and much more.
The real reason to doubt Jones is that how an athlete of his caliber not have excreted all the metabolites in 450 days since only people who have more body fat have higher chance of retaining these drug metabolites.
There is also one counter to this argument that since Jones was not cutting any weight, so therefore he did not piss hot for the previous tests but now since hes cutting weight, thats why USADA found 60 pg/ml of M3(Trust me, its a very very very small amount) in Jones body.