Duty Roulette - low level - same dungeons???

[Melinia]

31.10822386% - Sastasha Seagrot*(level 15 - 18)
23.00422866% - Tam-Tara Deepcroft*(Level 16 - 19)
19.1772825% - Copperbell Mines*(Level 17 - 20)

Doesn't the Low Level Roulette become available at level 20? Ergo, all three of these should probably all be the same percentages.