In Photo Tree RM7 would centre siblings whether there were 1,2 ,3 4 or more and if more that 4 place them centred on a second line.
RM8 can centre a single child or two children under the tree but with three they are offset to the left. In the case of five siblings RM8 places them over two rows; a row of three offset to the left and a second row of two placed one either side of the tree.
Again, a family of ten siblings are spread over two rows, nicely centred under the tree in RM7 but offset to the left in RM8.