Yes indeed, the cooler, denser air does cause an ECU to lengthen injector pulse duration because of what the o2 sensor is telling it.
An EFIE in the circuit can correct that to a large degree, and if your car is equipped with a MAP sensor, you can put an enhancer there as well to take a bit more authority over the injectors.
these modifications are akin to re-jetting a carb (and fine tuning the timing), but it has been some time since most people have had the inclination to get their hands dirty.
The small cost in parts and labour to bring these adjustments into the cabin makes for more fuel sales and more car/repair sales too.
I've just now noticed that your car is an automatic - can that sexy oil be used in the transmission as well?