The significance of the total percentage comes in with more advanced use of bakers percent/bakers math. For example, lets say your formula has a total percentage of 171%, if you have calculated that you need 10-pounds of dough to make something all you need to do is to divide the dough weight by the total percent. Move the decimal point two places to the left and divide: 10-pounds divided by 1.72 = 5.84-pounds of flour will be needed to make 10-pounds of dough by your dough formula. Another way to use it is to calculate how much dough you can make from a known quantity of flour. Again, our total formula percent is 171%. We have 6-pounds of flour, how much dough can I make? 1.71 X 6-pounds = 10.26-pounds of dough can be made from my 6-pounds of flour by my formula.
Here is another one, if I know your formula in bakers percent, and I add the percentages and get 162%, and I know that you made 7-pounds of dough, I can calculate how much flour you used, then I can make the very same size dough. 7-pounds divided by 1.62 = 4.32-pounds of flour were used in making the dough. Now I can calculate the amounts of each of the other ingredients to make the dough (this is just like the first example above).
Tom Lehmann/The Dough Doctor