not sure about cmax but had focus st with and the fittings went in on carpet just under seats. remember look at it well before driving off ,if your not happy dont drive away(bit of a pain i know). but its their error and you have every right to refuse it . it maybe right up underneath so have a good look. as these seats are removable that may be why the have to modify a bit. on focus only the backs fold down so no way of getting underneath.I know this is not the answer you wanted but hope it helps.