if your burning your four stroke oil in your furnace, or pouring it on the ground, your doing less good than a 2 stroke.
in a 5 hour ride, i went through 2-3 tanks of fuel.
at a 32:1 ratio that would figure out to 12 ounces of oil for 3 tanks.
if your like most four stroke riders, you would be changing your oil after this 5 hour ride, now, in a common bike, the wr250f, the oil level is 1.6 liters, which figures out to 54.1024363 US fluid ounces,
BAM! if your four stroke oil is destined for the ground, or for your furnace, you have roughly put 42 more ounces of oil into the earth at each 5 hour interval than their 2 stroke ancestors.
edit: not to mention that the four stroke oil is going to be 10X dirtier than the cleaner burning premix. they even make smokeless premix now.