Has Toyota set engine service light to come on at 5,000 miles, even if car serviced at 4,998 miles and light reset by mechanic??

My engine service light on my 2011 Toyota Camry consistently comes on at a
few hundred miles after oil change. I confronted mechanic for not resetting
light and was told that even if oil changed at 4,999 miles, the light would come
on again at 5,000 miles because Toyota had set it to do so. Is this assertion
accurate or is mechanic simply placating me to keep my business??