关于cpt的RFE

今天收到rfe的细节，要求cpt期间雇主都出信说明。整个cpt期间有2个雇主，楼主第一家已经离职一年多了。现在的这一家cpt period的时间不大对得上。请问这部分是必须要提供吗？因为如下没有写may sumbmit 而是写的provide the following。如果不提供或者少一部分会怎么样呢？

Curricular Practical Training

Since the evidence of record indicates that the beneficiary is or was participating in CurricularPractical Training (CPT), provide the following:

3)A letter from beneficiary's CPT employer explaining the beneficiary's job duties, pay and period of employment