Site Assessment Guidelines

My company is looking into LEED Certification for a new warehouse we want to construct and while looking over the credits, an easy one I thought we could attain was getting a site assessment done.  When I reached out to our Environmental contractor that does other work for us about doing a site assessment for our LEED certification I was told we should have a LEED Acredited Professional do the assessment and they seemed to not want to do it.  While I am studing to get my own LEED AP certification, I was wondering if this was a requirement for the site assessment that a certified LEED AP needs to do it?