It is logged.
My feeling is that the negative impact is that the CO must feel as if you are breathing down their neck. How would you feel, at your work, if your boss had assigned you a task, and you had started on it, working correctly to the best of your ability, then someone came and stood watching you. 'What are you doing now? Why are you doing that? Why aren't you doing something else? What will happen next? How long will it be till that other fellow answers you?' Imagine all the pressure from the telephone calls logged, from 100 cases, if they all picked up the phone without restraining themselves. I remember one forum member, who indulged himself with multiple calls and emails, who actually received a communication from the branch manager, asking him to cease harrassing his staff.
I always say, if your reason for calling comes down to only, 'I am here, waiting - tell me something,' then don't call. The CO WILL contact you if they have anything to tell you, or they need more information. Otherwise, it's polite to let them get on with their job. INZ has a strictly enforced routine of date-order working, so no amount of calls asking for updates are going to have the effect of prodding a CO to deal with that person's case more quickly, and in any case, a lot of the verification depends on getting answers from third parties, so if they haven't yet supplied those answers, there is nothing the CO can do but wait, until they have been able to tick off all the requirements.