My copy of QuickLOAD will give me 100% load density with powder charge weight equal to 0.987 x case capacity in grains of water. That seems about normal for an "unsettled" load. I have gone higher than 1.000 with other fine grained ball powders by tapping the case gently to settle the powder, even though QuickLOAD still gives me values below 1.0 for those powders.
But, none of that explains how to get 14.6 grains into a case with less than 14.6 grains of available space. Maybe Speer's cases have more internal volume?
And, calculating pressure is another matter. If the fired case is sorter than the resized case, we need to put the shorter length into QuickLOAD, which will then show a larger powder space for the pressure calculation.
It is a little "apples-to-oranges" to put the FIRED case capacity into QuickLOAD for the purpose of peak pressure calculation, but still have them calculate a loading density, which SHOULD BE based on a SIZED case.