Excellent, thank you very much for the additional information. I went to your picture page and watch the videos of your jumps. With an additional Hand grip, you will be able to bend the pole more easily. With a stiffer pole, it will be harder to bend, but will "give" you more on top - so you are correct in your thinking. With your jumps (watching on video) I would suggest going to a higher hand grip (one hand hold will make a difference) and try row/ put pressure on the pole longer. (It looks like you only row to your quads, get it down lower and get inverted!) This should help you stay tighter up on top (More inversion) and get more "spring" out of the pole and use the force into your body. Your takeoff is strong, last three steps look quick, and your step seems to be on. As you are holding about a foot down on the pole, a higher grip should allow you to easily move to a stiffer pole in the next year as you get stronger and faster. Remember, it is your speed at takeoff (last three contacts of your feet) that bends the pole, so a stiffer pole means you shoould be running faster (I really simplified that theory). As you train and get older, you will get faster and if you are holding at the pole's ideal grip, it will bend and unload as it was designed too.
With only one attempt at the higher grip, it can be hard to judge, but you are getting deep enough in the pits that I think a higher grip will help.
I will recommend bringing the next pole up in stiffness to meets though. If you have a sunny day with a slight tailwind, "Grip it and Rip it." Try that next pole - but I am sure you already knew that.
Your coach has done some pretty good work with you and as he has worked with you a lot more than I have, I would take his advice before mine as well. Hopefully I will be able to get up to the State Meet in SLU this year. If I do, hope to see you there!
"To give anything less than the best is to sacrifice the gift."