OMG, Burhan.
Have you not taken FSO training?
Here's the blurb from a course description.
I have done what you have in the course description for my employees who were authorized to fill tanks at my dive shop in NY. They had the course from PCI. We had also a very comprehensive step by step procedure list for running the compressor and filling tanks for dive shop tanks and customers' tanks. If a customer got pissed off, the heck with them but were were going by our safety procedures and my staff had proper training and authorization.
I asked you because I thought there were other issues and requirements that were cumbersome I didn't know about.