Part time H1B - Does Less Salary Concern Visa Officer?
There is no need to worry if your petition has already been approved by USCIS.
Visa officers at US embassies abroad are trained to understand these kind of situations.
Your employer would have already submitted the proofs to prove the number of hours you would he working and justify the position and salary.
This salary would have been backed by the ‘prevailing wage rate’ and LCA at your work location in USA.
You cannot really carry anything extra to prove this situation.
If your employer is reputed and they have provided all the petition papers, you should not have any issue in interview