Don't rate it as a very good method,but regards to the cells being bunched up is because they have not done it as advised,by destroying rows of larvae/eggs first. Prefer grafting from this faffing around.
This new comb freshly filled is ideal for cell building purposes. The best side of the comb is used for the queen cells and is prepared by destroying two rows of worker cells and leaving one, beginning at the top of the frame. This is continued clear across the comb. We will now have rows of cells running lengthwise of the comb, but if used without further preparation the queen cells will be built in bunches that will be impossible to separate without injury to many of them.
Accordingly, we begin at one end, and destroy two cells and leave one in each row, cutting them down to the midrib, but being careful not to cut through and spoil the opposite side. Some practice destroying three or four rows of cells, and leaving one to give more room between the finished queen cells.
We now have a series of individual worker cells over the entire surface of the comb, with a half inch or more of space between them. The practice varies somewhat with different beekeepers beyond this point. However, this prepared surface is laid flatwise with cells facing down, over the brood nest of the queenless colony, first taking care to make sure that any queen cells they may have started are destroyed. In general, it is recommended that the colony be queenless about seven days before giving this comb. By this time there will be no larvae left in the hive young enough for rearing queens, and the bees will he very anxious to restore normal conditions. Some beekeepers simply take away all unsealed brood, rather than leave the bees queenless so long. The only problem, if it is one, is that this method produces too many queen cells. Unless the queenless colony you use as a starter/cell builder is at peak strength with large numbers of young bees, there may be too many queen cells to be properly cared for. Not every beekeeper needs fifty to one hundred queen cells at a time. If your queen needs are less, simply reduce the number of undamaged worker cells. To damage or destroy the rows of worker cells on the comb face simply use your hive tool or a small stick to scrape across the cells to the mid-rib as if a line were being drawn. On new comb this is done quickly and easily.