This reminds me of “Why don’t they put leap days in July when it’s warmer?” You are also con­fusing mass and weight. We have to ask how is the gold weighed. If it is weighed with ref­er­ence to a standard weight (e.g. a mass balance) the ref­er­ence will also be lighter or heavier in the same pro­por­tion. A spring scale shipped from Helsinki to Mexico City (and not re-calibrated on site)would result in the (amusing) scen­ario above.