That is also true. The thing about your current recipe is that the types of oils you're using, most of them, can speed up trace. You are also using 20% cocoa butter, which has the highest melting point of the oils you have. You would have to soap with your oils at least 95F to lessen the chance of you reaching a false trace, which was more my concern for you.
For the record, I use 20% cocoa butter. Because of how my recipes are formulated, I tend not to have brittle bars when I cut loafs (If I use a loaf mold).
Modern Soap Making has and article about slowing down trace. As far as making less brittle bars, I would subtract 5% from the castor oil and allocate it to the palm or the olive oils as a start. You could also take a bit away from the cocoa butter as well. In truth, you may want to learn a bit more about how different oils behave in soap so you can better formulate your recipes.