This is dragging on, and going nowhere.
The issue is that Tesla doesn't publicly release their full test results for fuel economy under either European or US test cycles. They do release range specifications, but you can't convert that to consumption without getting crazy answers.
For example the Canadian P85 rated at 426km range with 23.6kWh/100km results in 236Wh/km for an 85Kw battery. OK, but 23.6kWh/100km for 426km range is 100.5kWh out of an 85kWh battery. Obviously the range is one thing and the fuel economy another; you can't calculate one from the other because of charging, vampire, and other losses.
The test specification of 'manufacturer's standard charging' is also hugely problematic - charging at 10A vs 16A vs 32A vs 80A are all standard, but would yield very very different efficiency differences and cause a wide variation in test results. Bring in battery balancing cycles, as previously mentioned, and the test is further compromised.
And that is the crux of the problem.
You can quite easily test a petrol car according to UNECE R101 and individually testing cars would probably give you a reasonable result for that one car. The result you get will approximate real world conditions on the same drive cycle.
But testing electric cars is vastly different. There are so many variables involved that the test results would vary wildly. Conducting these tests, with manufacturer involvement to ensure the test is conducted fairly, correctly, and optimally, is fine. But, conducting them without manufacturer involvement by people inexperienced with conducting them in the first place, leads to results that have no bearing on real life.
In my view, the mistake that the Singapore government made was in conducting this test on an individual electric car in the first place. There was no way it could produce a result anywhere close to being fair and comparable to the tests done on ICE vehicles.
