They based it all on R-12 and gave it an ozone depletion potential of 1, on that scale R22 for home AC was a .02, they say it's because a CFC molecule is stable and can make it up to the upper atmosphere before being degraded into it's components, the Chlorine of which is the "killer" of ozone.
Fun fact however: Ozone is created daily by sunlight, when it is dark at night there is very little ozone overhead and so it stands to reason a place that is dark 6 months out of the year would have an "ozone hole", especially when the light it does get in antarctic summer is coming from a glancing angle, not directly on like at the equator.
If chlorine was such an evil bastard, why was it never banned from swimming pools? My guess is that they would have got the same type of pushback they got when word came out they wanted to ban charcoal grills. I remember reading a story in the mid-90's that there was more dollar value of illegal R-12 being smuggled across the Mexican border than there was drugs.
But government "experts" are always right, and the last thing someone wants to be accused of is being a "science denier" tsk tsk....
