It makes sense. If write decorators as explicit function calls:

decorated = (
    deco1(
        deco2(
            original
        )
    )
)

The line number of decorator itself will be used for CALL_FUNCTION:

  2           0 LOAD_NAME                0 (deco1)

  3           2 LOAD_NAME                1 (deco2)

  4           4 LOAD_NAME                2 (original)

  3           6 CALL_FUNCTION            1

  2           8 CALL_FUNCTION            1

  1          10 STORE_NAME               3 (decorated)
             12 LOAD_CONST               0 (None)
             14 RETURN_VALUE

But I suppose this will add more headache for coverage.py.