I think I see the issue here.
At every leaf node, there is tissue that can form a new branch. If you look closely at a mango branch, there are regions of evenly spaced leaves and regions of tightly spaced leaves. As new growth starts, the leaves are widely spaced, and as that growth spurt stops, the leaves become tightly packed. look at the tip of a mango branch when it is dormant and you will see what I mean. If you look down the branch, from the tip, you will see evenly spaced leaves for a while, then a cluster of leaves or just a swollen knob on the branch. on your photo, follow the stem down from your lowest shoot, past one leaf and you will see the area I am talking about, a tight whorl of leaves and some brown scarring. Where you cut, the buds that were activated were from single leaf nodes, hence the stair step look of the new growths. if you were to have cut right above that whorl that I pointed out, you would have multiple shoots coming from around the same area (I would not suggest going that now). Let the current growth flush finish and harden off. when the next flus comes out and hardens off, cut it off about 1 cm above where this current flush ends and you will get the result you desire.