Window tinting and the long arm of the law

[chamb0]

A question about the legalities of window tinting in Victoria.

Today Mum had her old Ford Maverick wagon tinted. She wanted a nice tint in order to keep as cool as possible while towing around her horsefloat, and to prevent her horsey gear from fading in the cargo area. She is very keen however to stay within the confines of the law.

The advice from the tinter in person was that the regulations had recently changed in regard to wagons, and although 35% was still the legal limit for the front door windows, the rear door windows and the cargo area could now go darker. He said this was different to sedans which still require all windows to be no more than 35%. We said that we were happy to go ahead with this as long as it was legal. He assured us that it was, so on went PRE35% front and the rest MNM17%. They did a nice job of it.

However Mum has returned home and worried over the invoice, which states (for the 17% tint items):

THIS TINT TO YOUR VEHICLE WILL RENDER IT NON-COMPLIANT WITH ROAD TRAFFIC REGULATIONS. IT HAS BEEN APPLIED ON YOUR INSTRUCTION. WE WILL NOT ACCEPT ANY DIRECT OR INDIRECT LIABILITY FOR ANY COST OR DAMAGE AS A RESULT OF IT.

Looking online, I can't find any evidence to support the tinter's assertions that it's okay to go darker on the back. VicRoads still say:

All windows of a motor vehicle, other than windscreens, available to the driver to obtain a view of the road or other road users must have a light transmittance of at least 35%. However it is desirable that the light transmittance of windows to the side and ahead of the driver is not reduced below 70%.

http://www.vicroads.vic.gov.au/NR/rd.../0/VSI2web.pdf

As it stands, if her car is not strictly roadworthy, she will have it changed. Can anyone shed any light on this? Many thanks in advance.