Deoldify Vapoursynth filter

[Selur]

Got a question:

clip = ddeoldify(clip=clip, model=0, render_factor=31, sat=[1.00,1], hue=[0.00,0], chroma_resize=False, color_stabilizer=[False,False,False,11,"center",True])

should only call deoldify, right?
Strange thing is, when I change:

if dd_method == 0 or (dd_method != 1):    
        clipa = clip.std.ModifyFrame(clip, ddeoldify_colorize)

to

if dd_method == 0 or (dd_method != 1):    
        return clip.std.ModifyFrame(clip, ddeoldify_colorize)

speed increases form 7.77fps to 9.24fps.
It seems like I overlooked something and not only simple deoldify is applied.
Any idea what is happening?

Cu Selur