BRAKE INSPECTION HELP

[Abk911]

Hello everyone - before i ask the question below are my car details:

1. 2007 Yaris sedan, 4 door.
2. 99000 miles.
3. never changed bakes.

a year ago, the brakes started making a slight squeeling noise (still present)
but below are details:

1. Took to Toyota dealer last summer for a thorough brake inspection.
2. he said nothings wrong with brakes and while he charged 80 bucks for thorough inspection he did some tightning etc and set me off. the report also said 8 mm and 3 mm left on pads. and said you dont need to change rear brakes unless they are 0.5mm. he also said rear NEW brake pad thickness is 5mm usually.
3. then when i gave for servicing / oil change (mineke) - in his inspection report he gave 10 and 10 (very very wierd). not sure he meant mm or what,
4. so i waited a few months and then finally took to some local shop for an inspection. i told him to remove tires and check but he said since he is lifting the car up for an oil change he can check through a small "INSPECTION HOLE" BEHIND EACH wheel (i never knew there was an inspection hole behind the wheel) cause for my car its not possible to see the brakes through the wheel from front). he said 70% and 80% life left. and said - easily should last a year.

now my question:
1) how can there be such drastic difference in measurements for these 3 guys
2) how come the toyota guy says that rear thickness when new is 5mm and if thats so how come mineke one gave 10 and 10 written on his service form.
3) what do i do, shld i hold off a brake change or just get it done.
4) what are the actual original pad thicknesses and what thickness should i replace them.