Os pandas mudam a ordem das colunas no MultiIndex
df.reindex(columns= df.columns.reindex(['IWWGCW', 'IWWGDW', 'BASE'],
level = 0)[0])
Graceful Gorilla
df.reindex(columns= df.columns.reindex(['IWWGCW', 'IWWGDW', 'BASE'],
level = 0)[0])