Agree, I always did the same but SSS/CSS was a whole number.
It appears round my way that all courses have the same CR as the old SSS. Not convinced they have been re-rated, just a copy and paste job.
It could not be a copy & paste job as the old system has no provision for bogey and slope.
All women's courses and all men's, except England, have been rated using the USGA system for at least 10 years (probably longer). England men's course were rated under the old English Golf Union system which was similar to but slightly less sophisticated and had no provision for bogey rating and therefore no slope. The clue is in the expansion of SSS (Standard
Scratch Score).
Allowing for rounding, the figures for CR are virtually within 1 stroke of the old SSS nationwide. Differences outside that range are usually down to courses not being rated following changes made in the past. Courses were only required to have a check rating every 10 years.
England Golf introduced the USGA rating system a few years prior to and in anticipation of the introduction of WHS.
Edit. However, some English counties have not quite finished all their courses and those few will have been given temporary ratings.
Edit 2. doublebogey's comment above is pertinent. See my last sentence.