Step fixed cost?

step up cost / semi fixed cost remains constant upto a particular level of activity but after this level of activity the cost will changeand it will again become constant upto the next level

in this situation we will calculate bep for every level of activity of fixed costs and the bep which for in the same block of activity for whose f.cost is calculated will be taken as valid bep and others will be invalid bep

and one more thing in this situation there can be more than one bep and it is also possible that there will be no bep