Stagpanther,
No. There's nothing special about doing that. If you look at QuickLOAD's various inputs, you'll see one called the Weighting Factor. That is the portion of the charge pushed forward with the bullet. Powder ignites near the flash hole first, so it builds pressure and starts pushing on the powder column before the flame front has propagated fully through the powder mass. If you use a stick powder and recover an exposed base rifle bullet from your backstop, you clearly see the outlines of the grain sticks impressed into the lead. So forcing powder to funnel out of the case mouth happens anyway. You're not introducing a special issue.
The only thing with QuickLOAD you have to watch out for is that it doesn't directly tell you the effect of the bullet shoulder being close to the throat of your bore. If you hover the cursor over the start pressure, the instructions tell you to add 7200 psi to the usual value to allow for actual contact with the throat (a jammed bullet). In my experience, that extra start pressure's effect on typical tangent ogive bullets has disappeared by the time you are about 0.030" off the lands. The effect is not linear, but I figure a linear interpolation is probably close enough, so I add about 2400 psi for 0.020" off the lands and 4800 psi for 0.010" off the lands until I can test it with a Pressure Trace. Anyway, if you are seating your bullet out further to get more powder space, that it something to consider.
QuickLOAD's pressure calculation is an estimate based on measured powder properties. SAAMI uses measurements to determine load values, but the data below, which came from SAAMI's 1992 and 1993 centerfire rifle and handgun cartridge standards, respectively, show that the absolute measurements made by different labs using the same calibration method have pretty wide variation, so any one measurement of the average of ten rounds (SAAMI's standard approach) doesn't actually do any better than QuickLOAD does.