Are these two parameters elevation and flatness set incorrectly/reversed in code and the paper?

[Charlie-lusie]

As the title, I found this in the paper:

for elevation: e = mean(E) + a_m * stdev(E). All a_m=1.
And for Flatness， f = mean(F) + b_m * stdev(F), b=3 for m=1, others: b=2
But in code:

double update_mean = 0.0, update_stdev = 0.0;
calc_mean_stdev(update_elevation_[i], update_mean, update_stdev);
if (i == 0) {
params_.elevation_thr[i] = update_mean + 3 * update_stdev;
params_.sensor_height = -update_mean;
} else {
params_.elevation_thr[i] = update_mean + 2 * update_stdev;
}
double update_mean = 0.0, update_stdev = 0.0;
calc_mean_stdev(update_flatness_[i], update_mean, update_stdev);
params_.flatness_thr[i] = update_mean + update_stdev;

Apparently flatness uses 1 for stdev, and elevation uses 3 and 2.