I believe the idea was "Very High Tarrifs" and the formula was some kid in MS Excel . They are definitely not reciprocal. They don't need to be, since the plan was to use the high tarrifs as negotiating tool to somehow reduce the US national debt
Article links here which explains how they did it, with reasoning and references: https://ustr.gov/issue-areas/reciprocal-tariff-calculations
> The recent experience with U.S. tariffs on China has demonstrated that tariff passthrough to retail prices was low (Cavallo et al, 2021).
The line that says "sure, tariffs won't cost consumers _that_ much", and they don't even have a bibliographic entry for Cavallo et al. 2021.