The $60'000 cap for US investments

so would you agree that the following describes the US estate tax situation correctly:
upon death, if you are a swiss citisen or resident,
below USD 60’000 of US-domiciled assets no taxes apply. Above 60k, the old Siwss-US-taxation treaty from 1952 kicks in: the tax-free limit is calcualated as
$5’230’000 * f
where f is the fraction of US domiciled assets of your total belongings.
Of your US-domiciled property, everything above the threashold is taxed roughly 40% (who knows?)

Example: if you are 100% in US domiciled stocks, you tax free threshold is $5.23M. if you have 20% of you assets in the US, it is $1.46M

Source NZZ
Source Deloitte
Source Credit Suisse