yes, that's on top of the so called post adjustment that for e.g. Geneva (last time I looked) was around 96% (base salary + post adjustment = net salary (+ normal tax rate) -> gross salary in the private sector (30 working days holidays p.a., up to 70% pension levels (17years contribution) with 5 years+ contributions getting you a pension, for senior staff add no VAT, 50% lower petrol prices, real tax & duty free shopping everyday - about half or less your airport shop, etc etc etc)

...and as salaries are normally paid besides tax free also tax equalized (the US is demanding income taxes from all citizens wherever they live including UN staff - the UN covers these taxes for US citizens and a handful other countries) the US pays itself back (via income tax) a nice discount of certainly 10% of its contributions to the UN.