I guess I'm not following 100%, if you're asking if the judges changed a particular score then no, as that can't be done without a written inquiry. (Even then highly unlikely) If you're asking if the coach approaching the judges table influenced the scores following, then I guess that could be...
True statement by jago, as there are several instances where the judge may be asking the coach a question about gymnast order, warm-up/touch procedures, equipment, etc. I will tell you as a coach, sometimes the discussions we are having with the judge is irrelevant to gymnastics completely.
Most coaches/ judges have good relationships and do ask questions regarding scores, start values, etc. Technically however, coaches aren't supposed to ask the judges directly. Instead, coaches with questions regarding such things are supposed to write out an inquiry and present it to the meet...
I would advise following the direction in which your coach feels is best, as he/she is doing what he/she feels is in your best interest. You have to remember we as coaches don't benefit from you not doing something, so it's fair to assume if we don't feel your ready it's because you aren't.
It all depends on the gymnast, although it's sad that the tusk is becoming a skill of the past. IMO a full twisting tsukahara or kasamatsu is a more dynamic vault, and would love to see more of them. As a level 6/7 I like to work both vaults to get a feel for what each gymnast would better...