Boost leak and compression test because low on oil? That's a new one. First look for seepage around the valve cover gaskets. And look for drops of oil running down the oil filter from a bad oil cooler gasket. Rule out external leaks before assuming you're burning oil. Any smoke from tailpipes?
Did you check your oil after adding the 3/4 quart? You were probably a couple of quarts down if the dipstick was completely dry. I'd be more concerned about your bearings and turbo than anything else.