Not only that, Banishment is AoE 2+(2* H level), Dam 3+(2* H level). According to the spell spreadsheet, not the manual, it's even range 15 + (5* H level).
H1: AoE 4, Dam 5, range 20
H2: AoE 6, Dam 7, range 25
H3: AoE 8, Dam 9, MR-1, range 30
H4: AoE 10, Dam 11, MR-1, range 35
H5: AoE 12, Dam 13, MR-2, range 40
(Extra bonus points if you go to the all effort of making an H5 priest just to cast banishment
)