For anyone who is genuinely interested in interpreting Basso's numbers, I suggest you have a look at some graphs in this article
http://www.haematologica.org/cgi/reprint/88/9/1053. See the top of page 1059 (that's the page in the journal, not the article length, in case anyone is wondering).
Notice how hemoglobin concentration spikes quickly up then down at the start of altitude exposure, then begins to climb more gradually again. I'm not a heamatologist, but I believe any analysis that doesn't consider how blood values vary during an altitude training block is incomplete at best. My understanding of the explanation for the trends in Ashenden's graphs is as follows:
Plasma volume decreases on initial exposure to altitude, which means red blood cell concentration/hemaglobin concentration/hematocrit goes up, but not the total number of red blood cells. This effect is quite short lived. Over a few weeks, hemoglobin concentration gradually rises in some athletes, this time because of an altitude stimulated increase in total red blood cells. This only works well with live-high-train-low and only if the athlete has enough iron in their system. I don't have time to dig out all the references now sorry.
If we assume that EPO dosing happens both before and after blood donation then mitochondria's explanation makes sense too. However, from my limited knowledge I believe that altitude effects are also a perfectly reasonable explanation.