I realize this is total necro, but this post shows up on the first page of DuckDuckGo results.
I was getting Ds and mostly Fs on DSL Reports bandwidth test.
In 2.4.2, setting CODELQ without bandwidth was not permitted by the interface.
Setting bandwidth to a number higher than my ISP advertised rate resulted in no change in bufferbloat.
Setting bandwidth to my ISP's advertised rate resulted in all As.
What I found interesting is that even though I can get ~10% higher than advertised actual speed, setting bandwidth to even 50 kbps higher than advertised resulted in increased bufferbloat.