Hi - yeah, because interactive proofs can be viewed in different resolutions, the page you are seeing is not necessarily the same as the next person.
For the agencies that do interactive proofs, we recommend that they pick a standard resolution that everyone uses for that "version" and that the first stage (which is Proofreading for us) comments on every page. So if there is nothing wrong, they will still say "Looks good" so a screenshot is taken and we can verify every page has been looked that.
Hope that helps.
