would you attach a workbook to get help faster?
In your if then statements I think you might need an else clause to handle when the value is there.
But as Deepak said, upload a workbook.
I'm assuming the rows with null values are not required for your analysis.
If yes, then make a copy of [#Utilizer Parameter(Charges)].
Then add [#Utilizer Parameter(Charges) (copy)] to the filter shelf. Select Null and Exclude.
Then go the original [#Utilizer Parameter(Charges)] filter. Right click and select 'Only Relevant Values'.
Hope this helps.