I follow you now - your doing press-to-metal. Something you may want to be absolutely certain that you are doing is when your waxing, to wax a short "tang" or "fish hook" or "T-bar" on the lingual side of the coping to prevent the copings from shifting in the investment while being pressed. There is alot of pressure coming down during the pressing process. These little stabilizers lock the coping in the investment and prevent any movement during processing.
As stated in an earlier post is making sure you are keeping true to the manufacturers recommendations on minimal metal thicknesses to prevent bulging or deformation. Generally, higher gold content alloys have to be a little thicker than semi-precious ones.