My physics textbook emphasizes that the electric field appearing in Gauss's law is the resultant electric field due to charges present both inside and outside the chosen closed surface , while the 'q' appearing in the law is only the charge contained within the surface. .This appears to follow from the mathematical statement of the law as the flux due to externally present charge is ,naturally , zero. But this also seems to suggest that the electric field on the Gaussian surface ( say a sphere ) would be the same whether there is solely one point charge ( which the sphere encloses say ) , or whether there are in addition a collection of point charges present outside the surface. But this cannot be true , can it ? Is there something I missed?