This is VERY normal for the 4.6 motors. I owned a 93 Marquis that started burning at 150k. I would burn about the same amount in at the same intervals you mention. It still burned the same amount at 233k when I sold it. Try running a a additive that slows down oil burning. I did it in mine and it helped a little. I am to understand that the Valve seals go out on these causing the burning issue. You could fix that but I am told it really isn't work fixing.
Short of a rebuild there aint much you can do about this one. MANY of these cars burn just like you described.
70 Camaro SS // 87 Mustang GT Conv - 119k
93 Z71 - 264k // 01 P71 - 87k // 05 Dodge Magnum R/T - 122k