Whether 'rhythmic difficulty' is different to 'actual difficulty' is besides the point, which was that DT is easier to acc and to FC than nomod.
Acc is quite overweighed on maps like Setting Sail, I average around 97-98% on 5* od8 nomod, and even though that's od9.6 I could get over 99% pretty easily. Same with Diasy [Blossom], I got 98% on that at OD10 because it's all 1/2 jumps with no streams, any other 5* map with HR and I'd get 90%.
Setting Sail is objectively easier to get pp from than Swing It because the difficulty of getting high acc on relatively easy high OD maps that are all 1/2 jumps is much easier than getting low acc FCs on harder nomod maps.