In my opinion them dents help you rather than hurt you. This is the area where material (also a few rocks in your situation) makes transition into rear feed. If you look closely you will see that area of floor is humped up from the factory. I'm told by engineer this hump was designed in to prevent mud buildup. When we lower the floor we remove the humped area for I believe it is screwing up the straw flow more than preventing mud build up. This floor does need to be replaced at some time. There is a great difference of lifetime of floor. Check with local dealer to see what average hours for the crops, conditions, and area you are in. For our area on average your floor would be 3_4 wore out. The currant production floors and replacement floors are twice as thick as original so they should last twice as long. I would surely have your dealer check with me or our website if he is going to replace floor. Especially if your area can experience premature feeder plugging. That feeder is not to narrow and can handle tremendous amounts of straw with a little modification. Hope this helps.