I am not sure that you are attributing things correctly to the USADA and their scientific knowledge. If you think that the USADA truly believed that you could "ingest EPO" and that would make it appear in samples whereas small intravenous doses would not, you know absolutely nothing about what you are speaking of. EPO is a protein - any protein you "ingest" will be digested by your stomach and will neve appear in any urine test as it will only remain in its most simple form - amino acids.
If the USADA actually thought that you could ingest EPO and they could catch you then they are even dumber scientists than they already come off as.
I am still waiting for someone to truly show me that they have caught Lance cheating, not that they have decided to modify the rules that say you are cheating after the fact. Nor have I seen how the USADA is accounting for the fact that at least once in the timeline that they say that Lance was using EPO that the manufacturers of EPO changed their formulation of EPO which changed the way that EPO would appear on testing because the ratios of the various isoforms changed and caused some severe problems. Look up "Pure Red Cell Aplasia" and look for its links to EPO and the formulation change (or even the ridiculously high incidence of PRCA in Asia as a result of many new types of EPO that have flooded the market as biosimilars).
Still waiting for some truly scientific proof.