I am wondering if more feedlot beef is creeping into the parrilla meat supplies
and the cooks just don't know that it doesn't cook the same way. Beef quality is, unfortunately, down over the past handful of years, and it doesn't look like it is going to go back up anytime soon. I've generally never had a problem with overcooked meat in BA, in fact, a lot of places historically refuse to cook it too well done, because with grass fed beef, you can't really eat it.
The best beef I've eaten in the capital has been at La Brigada, but I haven't been in at least a year. El DesNivel is variable, but it is convenient. El Pobre Luis, one visit, it was acceptable but not worth a trip across town (in March). My "parrilla del barrio" run of the mill places have been extremely variable, from meh, to pretty good. No home runs in quite awhile.