How Much Bone Graft Volume is Adequate for a Sinus Graft?

Dr. E asks:
In general, how much bone graft volume — in cubic centimeters — is adequate for sinus graft procedure in the areas of #2,3,4 [maxillary right second molar, first molar and second premolar; 17, 16, 15]? In this case, a pre-operative CBVT scan showed only 4-5 mm of vertical bone present below the sinus floor. The mesiodistal and buccolingual widths of the sinus were large on the CBVT scan. After the sinus grafting procedure in this region, panoramic radiographs showed excessive lift – especially in the #2 area, where the sinus bone graft is superimposed on the orbital rim. Will this pose any post-operative complications in the future? There was also a small tear in the sinus membrane that was repaired at the time of grafting using Biogide [Osteohealth] resorbable collagen membrane. Could this excessive bone fill be due to the distortion of the panoramic radiographs? Should I remove the excess bone graft? This is the first time that I had to use almost 10 cc of bone graft.