Yep,.. works a treat too.
I used to do them with a powerwasher off roof ladders,.. but way to slow, too dangerous, to cold etc. I was getting €600 - €700 a time for a 4 bed bungalow/dormer.
The spray is chlorine based and kills the algae & lichen,.. and a 2 day job can be done in a half hour,.. 1/4 the time,... but still 1/2 the price!
I'm still testing the chemicals on different types of roof tiles, just to make sure nothing reacts (I test an inconspicuous area on each roof first too)
Obviously it doesn't work when the moss is really heavy & thick,.. but I'm testing to see if a double treatment will do the job.