I would like to ask you all, if some of you have implemented Zero Based Budget concept in your planning and which line of the P&L ?

when i use zero based budget and incremental budget

in practice when i measure variance between actual and budget and i get big variance With no unnatural factors affecting the results so its mean i have problems for buliding budget and i have to begin again from zero to understand problem and follow up effects that case variance , it means zero based it used when you have problems and try to solve it From the root.so for p&l you will follow up al expenses by details and  justify for this expense