That makes sense, thank you. I was really noticing the particular angle of the tilt in many icons I have been showed. It just looks odd to me for some reason. :) But perhaps many of those I have seen were from the same general time period, and that was simply the artistic style of the time.
The style of icons is in itself a matter of canon. It is not simply an artistic preference similar to artistic styles in creative art. For example, iconographers are taught to avoid excessive realism. The drapery folds are supposed to be schematic; the fingers are supposed to be innaturally long and smooth, mouths small, landscape and other accessories minimal, etc. It is a whole expressive system designed to expose the spiritual essence with maximum clarity.