RFE on F1 Maintenance of Status- CPT Document Required- Letter from Employer

The are seeking a letter from all CPT employers to confirm you are working within your major. Mr. Smith is an attorney with over 25 years of immigration experience with complex immigration issues and successful filings. His response to your question is general in nature, as not all the facts are known to him. You should retain an attorney experienced in immigration law to review all the facts in your case in order to receive advice specific to your case. Mr. Smith's statement above does not create an attorney/client relationship.

From your statement, it appears that CIS is trying to make sure you have maintained lawful status under your F1 terms so I would include all employers you have worked for while on CPT. Pay close attention to the questions on the RFE.

All of the employment. They want to know whether you did not exceed the allowed CPT period.

It clearly states "Employer(s)" so if there were more than one then you will get one letter from each employer.