What model year is your Vios and what's the numbers for individual Rear toes and Front toes?

Your technician comment on rear cambers of -1.65° left and -1.35° right is Internet 'wisdom' popularly published ........ which sometimes is NOT true for one of the rear tyres.

Your rear toes of Left and Right tyre will reveal angles that actually cause 'accelerated' rear tyre wear, either even wear or uneven wear pattern.

For reduced wear rate, it is essential to adjust rear toes rather than the rear cambers, which in your case the rear cambers provides greater safety and vehicle stability in taking corners or turning. The chances of 'dangerous' oversteer phenomenon is reduced considerably in your case.

Hence, do consider keeping the existing rear cambers but have the rear toes adjusted to minimal positive toe in's, if you so wish.

The technician is correct in saying the rear toes and cambers in a Vios can't be adjusted, with toyota parts or by service centres.

However, it can be done with shim method which fortunately is available for you in a Kempas JB wheel alignment shop.

Go to Post #2 (or is it Post #1) of this thread, under list of alignment shops ..... look out for some contact details of the shop.... which i think is Jettsin or something.

Edit: The front individual toes can influence whether it is outer edge wear or inner edge wear on rear tyres with excessive Rear Total and individual Toes.

Excessive rear negative cambers does influence whether it is outer or inner edge wear, BUT in itself does NOT cause excessive tyre edge wear if you know what I mean.

Wow.. 4-5 times of mount and unmount of tyres with nearly 2 hours. A shimming job could indeed be quite a 'headache' for a pro.  Imo, RM80 for shimming is really value for money for owners of cars whose rear axle is either Rear Torsion Beam or live solid axle - in which the Rear cambers and toes is supposedly not adjustable.

+0.20° Rear Total Toes would be having normal tyre wear rate, even at rear cambers of -1.20° or more negative.

However, if individual rear toe for one side is +0.20° with the other side about the same ...... then you're going to have 'accelerated' abnormal rear tyre wear rate despite of less negative  rear camber of -1.20°.

Hence you may want to ascertain that the +0.20° mentioned is Rear Total Toes.

Yes, it is Ah Bao whom I had contacted about my Avanza rear live axle shimming proposition. Unfortunately he is of the opinion shimming can't be done on my rear wheel drive RWD Avanza. 2-3 other mechanics I contacted has similar opinion as Ah Bao's.

However, I still believe shimming can be done on a Rear Wheel Drive Avanza like mine ..... hence the search  continues ...... hopefully someone would do it for me in years to come.

Btw after current wheel alignment, do your steering wheel off to one side whilst driving straight ahead ?

Does the Vios drifts or pulls to one side without steering input?