jstarr, 4 ounces is a bit small for my tastes, and if a hunk o' tenderloin is cooked for that long, i'd think it would come out fairly well done. yuk.
it's a delicious cut of meat that should be enjoyed rare to medium rare, imo.
you could follow those instructions, but with more like 2 eight or 10 ounce pieces.
i would cook the (8 ounce, salt and peppered) meat over high heat for 4 minutes a side, then remove it from the pan.
then add the wine, bring it to a boil, add the balsamic, reduce the heat and let it reduce by at least a third. put the meat back in, spoon with the sauce for a minute.