After i clear the data the row number in formula is changing

Hi,

I have a file with 9 worksheets relate to the productivity of several production lines. At the end of the week I need to clear all the data from this sheets in order to fulfill them for the week that is starting. When I hit " Data clean end of week" button, in 3 of the sheets the row number from the formula wich is used to  calculate the data, is changing. From example the correct row number is R167 but it's changing in R165, where is not the value but the text ( is the day, Monday,  Thursday, etc.). I have to mention that is a Macro behind all this.What is wrong with it? Thank you in advance!