Hello,

first of all, you are using a outdated version of JAG3D. I recommend to check the latest version.

Concerning your question, in geodesy, we use two terms to describe a deviation, i.e., error and correction. Both terms have the same magnitude but different signs. A correction is added and an error is subtracted, i.e.,

$l=l_0+corr$ vs. $l=l_0-err$.

Regards
Micha