No, we are not saying your tree is weak. In fact, it looks like it had a healthy growing season. It is more that grafting plants onto rootstocks has a range of reasons, one of which is to ensue a robust rootsystem, which is capable of dealing with a wider range of soils, and is less prone to infections, in other words: To ensure strong healthy plants. There are however lots of reasons to graft. Have a look here if you want learn more:
en.wikipedia.org/wiki/Grafting
www.nola.com/entertainment_life/home_gar...94-cb403dc237aa.html
www.hardyfruittrees.ca/tutorials/2014/01...-fruit-trees-grafted
In order for the roots to live, during the layering you will have to get some buds to sprout below the area that you are layering. Now if I look at the picture, I can identify a range of areas where buds COULD form (red lines). However, as they have not done so yet, I am uncertain whether it will. Which is why the suggestion made by Hansen originally to layer above the first branch. The blue line is where the plant was grafted. You see the chopmark? low chomarks with just one branch are a telltale sign. Then you look carefully and you see the bark above and below the chop are different: andother mark of grafting
Taking the upper part, the red lines are where you could consider layering. By making the upper cut at a slant, as shown, you can create a slanted rootbase, which will allow you to plant the layered tree at an angle, and your new trunkline could be the blue line.