USNGtoLL returns incorrect value

[monkeytroy]

I am using USNG to build a grid and all the USNG zones seem to be one number off.

let usngConverter = new usng.Converter();
let centerCoords = usngConverter.USNGtoLL('4Q', true);

centerCoords is set to {lat: 19.828721999428463, lon: -163.77045633905962}

Which is incorrect according to other conversion sites. That seems to be the center of zone 3Q.

Put those coords into https://www.ngs.noaa.gov/NCAT/ which confirms the USNG value is 3QXB2876292996