There are several distinct species grouped under the trade name "vitex", depending on country of origin. Joint Groups are related to wood density. New Guinea vitex (Vitex cofassus) has a density range of 645-720 kg/m³ at 12% moisture content, according to a CSIRO publication (Characteristics, Properties and Uses of Timbers, vol. 1, South-east Asia, Northern Australia and the Pacific).

We feel there could be a typographical error here. As far as we are aware there is no Australian Standard AS 9057. There is a European Standard ISO 9057 dealing with glass containers, which you can find on the net. If you have a link to AS 9057, let us know. Otherwise, our Regulatory Information Report RIR 41117, version 11.0, complies with AS ISO 9239.1-2003 Reaction to fire
tests for floorings Part 1: Determination of the burning behaviour using a radiant heat source. 

Large hardwood fence posts could be used to build a free-standing carport but there are a few factors to consider. You will need to obtain building approval from your local Council and they will want to see a design, plus structural calculations. To work out whether the posts can carry the load, and at what spacings, a structural engineer would generally need to know the type of timber and its stress grade. Matters such as how the posts are supported at their base, how the carport is braced, and so on, will also need to be considered.

Flooring is normally supplied at a moisture content that is ready to install. Your supplier may be able to confirm this, or test the timber for you with a moisture meter. If unsure, or if the property is likely to be unusually dry or damp, it is recommended to 'acclimatise' the timber by removing any protective wrapping and storing it inside the building. This allows its moisture content to adjust to an appropriate level. The flooring will only cup or warp if it undergoes a significant change in moisture content.

Your problem looks like a case of iron stain with the attached image showing typical blue/black stains around fixings. When tannin in the timber comes into contact with iron in the presence of moisture, black stains can occur. This is explained in more detail in a data sheet published by the US Department of Agriculture's Forest Service. A copy can be downloaded via this link https://research.fs.usda.gov/treesearch/48449. We weren't sure what kind of fixings were used on the deck and fence.