Paperwork: US Embassy vs. INS
 

I am about to return again to the US on a non-immigrant visa and intend to apply for a change of status to another visa once there as I have done before.
My question is, do the INS have copies or direct access to the paperwork that I submit to the US Embassy when applying for my visa in my home country?
My present company in the UK are willing to write a letter stating that my job will remain open (even though they know that I will be away for longer) for me to return to work upon completion of my visa in the US.
Will the INS question this when they come to review my change of status application or will they not be aware of that paperwork, assuming that the Embassy made the correct judgement in granting me the original visa.
Hope this all makes sense!
Thanks.