There is no reason to use the internal offset registers. Simply apply the six correction factors (3 offset, 3 scale factors, expressed as floats) to the raw readings in the Arduino code.
Example for one axis:
float ax_corr = ax_scale*(ax_raw - ax_offset);
To check that the corrections have been applied properly, rerun the calibration step on the corrected values. You should end up with three new offsets = 0.0 and three new scale factors = 1.0.