Your Thom Index (THI) is wrong

[Percherie]

Hello,

I use the Thom (THI) to obtain a comfort index.
The simplified formula is (valid for C°)
THI = T - [(0.55- 0.0055 . U) . (T- 14.5)]
Source : https://www.institut-numerique.org/i51-leffet-combine-de-la-temperature-et-de-lhumidite-de-lair-les-indices-thi-et-humidex-502a31728eec6

Interface for HA "Comfortable Environment Card
https://github.com/argaar/comfortable-environment-card
has used the work of the National Weather Service for its calculations and arrives at the same results using the complete and detailed formulae
https://www.wpc.ncep.noaa.gov/html/heatindex_equation.shtml

For example, with 19.4°C and 42% U, the THI should be 17.8369 and you tell me that the index should be 15.37.
"The Comfortable Environment Card gives me the right information.

I suppose there's an anomaly if we use F° or C°.
Can you make a correction along these lines?

[Percherie]

For example, with 19.4°C and 42% U, the THI should be 17.8369 and you tell me that the index should be 15.37.
"The Comfortable Environment Card gives me the right information.

I'm confused,

I came back to this ticket and I don't know how I found the numerical value of the Thom (THI) in Thermal Confort.