The tubes come that way. It is the mechanics of the tube that create a little extra space at the bottom. They will not wind down any further. Any of the tubes we have sourced are that way.
We fill our lip balm tubes by hand, as full as we can. Many times people never notice it because the tubes are not clear. The .15 oz weight on the packaging is accurate for what is in the tube. That is the weight without the tube.