The following notice from Red Book Guide relates to information contained in their guide, including the values. Please read this notice carefully:

Price Variations
All vehicles within this guide are said to be in "guide condition". Any variations may affect a vehicle's value, and allowances should be made for these. Listed below are the major factors affecting a vehicle's value.
Condition:
All vehicles are assumed to be in "guide condition" an explanation of which is in the "Definition of Guide Condition" section. A vehicle that is in either a substantially better or worse condition than outlined in this section, may require both the trade and retail figures to be adjusted accordingly.
Kilometres:
The bulk of used passenger vehicles that come onto the market within four years of their initial sale as a new vehicle come from one of the fleet areas, government, business or rental. Such vehicles, because of the environment in which they operate, average between 15,000 and 25,000 km per annum. Those vehicles that have travelled substantially more or less than the higher spec vehicles of this parameter may require the trade and retail figures to be adjusted.
After five years the bulk of the passenger vehicles are in the hands of private owners, at which time the average distance a private owner will travel each year is 16,000 km. Fleet vehicles generally incorporate both business and private travel in their annual distances, while privately owned vehicles annual distance is generally just that - private km. From the time they are new, most prestige vehicles travel an average of 10,000 and 15,000 km per year.
Our approach to annual km allowance is reflected in the right hand column beside each vehicle. The odometer allocation starts from the date of a vehicle's release and is adjusted each month.
Equipment Level: All vehicles in this guide are valued with standard features and do not include any optional extras. Optional extras can affect a vehicle's value; therefore any extras above standard equipment levels may require both the trade and retail figures to be adjusted. Suggested option values are contained in our "Option Values for Used Vehicles" section. This table will assist you in estimating the increased value of a vehicle depending upon its equipment levels.
Regional: Values for like vehicles of similar age and odometer reading can vary between state, city and town in Australia. Considerable variances that exist between metro and rural valuations are now even more obvious.
These variations occur primarily because of local supply and demand factors. A vehicle being sold in an unfamiliar environment will also impact on its value. Such vehicles need to be assessed on the basis of the local market environment.

Note:
1. These adjustments may themselves vary during the course of the year due to regional influences, supply and demand and seasonality.
2. Darwin values will range by up to 10% - 15% variance over the year. Values tend to fall to the lowest comparison point during the wet season.

Guide Condition Defined
Engine: Operating efficiently and showing no abnormality regarding oil or fuel consumption, compression or engine bearing wear. Exhaust system free from cracks and leakages.
Cooling System: Operating efficiently.
Integral Construction Members: Free from cracks, other serious defects and repaired fractures; also free from distortion, looseness of any joints or excessive rust.
Transmission: Operating efficiently with no abnormal play or noise; free from oil leakages. Clutch or torque converter efficient in all respects, and not requiring immediate replacement.
Suspension and shock absorbers: Sound and operating efficiently.
Steering: Operating efficiently. Wheels correctly aligned, joints and bearings free from abnormal play.
Brakes: Efficient in all respects and not requiring to be relined or replaced immediately.
Tyres: Sound and having a legal level of tread and complying with State roadworthy regulations.
Electric & Hydraulic Equipment: Alternator, starter, ignition, lighting, control gear and other electric or hydraulic equipment functioning efficiently; battery able to hold charge; wiring and connections in good order. Bodywork: Sound and reasonably well maintained; free from dents or with any damage repaired. Paintwork polished. Doors, windows, sunroof, hood etc. operating correctly.
Upholstery: Reasonably well maintained and free from unsightly repairs, stains and burns.
Registration: Complying with roadworthy requirements in all respects. Value may be influenced by the remaining registration.