CPT allows for contract role?

Hi, I have a full time CPT letter from a consulting company where I will be working for one of their clients. Which I would like to use to cover 3 credits of my course. My DSO said its okay to work as a contract role after looking at my offer letter. They just checked for start and end date, hours and job description. I’m worried if this is an issue from their end or if it will cause any issues for me in the immigration or while applying for OPT/STEM OPT in the future. Any leads are highly appreciated and would be greatly helpful