The following are graphs showing the difference between the values of density of a higher level block X (green line) as compared to a lower level block Y (red line) that is a neighbor to block X to the left in the x dimension. This particular case can be seen as the source of problems in the form of seams that can be seen in images here: http://flash.uchicago.edu/~jbgallag/cc
The graph of the neighbors data (red line) is the resultant data after injection, meaning that the correct portion of the data was copied from the neighboring lower level block and inserted into the higher level block. The data shown are the 2d planes that are copied from a neighbor and in this case (N^2)/4 cells are copied from the lower level neighbor from the proper place within the block spatially and then these cells are inserted into the full (N^2) cells as ghost cells for the higher level block. Most likely the seams are occuring at blocks such as 1259, 1263 , 3085 and 7041 (to name a few) where the difference between the values is the greatest.

Block 1257
Block 1259
Block 1261
Block 1263
Block 3080
Block 3083
Block 3085
Block 3095
Block 3099
Block 3101
Block 3103
Block 3105
Block 4119
Block 4121
Block 4123
Block 4125
Block 5153
Block 5155
Block 5165
Block 5167
Block 6072
Block 6075
Block 6077
Block 6079
Block 6137
Block 6139
Block 6141
Block 6143
Block 7041
Block 7051
Block 7053
Block 7055
Block 7058
Block 7061
Block 7063
Block 7065
Block 7068
Block 7071
Block 7073
Block 7075
Block 7078
Block 7081
Block 7083
Block 7085
Block 8455
Block 8457
Block 8459
Block 8461
Block 8474
Block 8477
Block 8479
Block 8481
Block 8519
Block 8523
Block 8525
Block 8527
Block 8538
Block 8541
Block 8543
Block 8545