One feature that I've just discovered does work with the smooth reflections app is the long exposure noise reduction. I had assumed that this feature gets switched off the same as the electronic shutter as soon as you go into the app. However, I was shooting some high iso night shots (3200 iso and 20 seconds) last night, and noticed that I still had quite a lot of noise and speckle, even when using the app to combine multiple shots.
On a whim, I turned on the long exposure noise reduction and found that it not only works, but also gives a substantial reduction in speckle across a 4-image exposure compared to when the same number of shots without it were combined. Comparing a single image with long-exposure NR against either of the four shot images, the big gains for the app were not only in overall cleanliness of the image, but also in the saturation and colour rendering.
In addition, the 4-image exposure with long exposure NR is definitely superior to an 8-image exposure without long exposure NR - in other words, at high iso, diverting half of your exposure time to dark frames via the long exposure noise reduction setting, gives an additional gain over the smooth reflections app on its own.
-John