I was taught that each stop halves/doubles the light throughput. So one stop up is double as much light, one stop down is half as much light.
Now, according to this Rosco table: https://www.rosco.com/filters/ecolour.cfm Filter #207 has a throughput of 33%, that equals a 1 stop light loss.
Why? If one stop is half the light, then 50% throughput should equal 1 stop, and 33% should equal about 1 and 2/3 stops.
In the same way, according to the table, filter #208 has a throughput of 16%, that according to the table equals 2 stops. Isn't 2 stops supposed to be 1/4th of light, so 25%?
Where is my mistake?