Late charges calculation interval

Hi,

I need to calculate late charges for over due payments to be 0.3% per week.

So if the over due days less than 7 it shouldn't calculate any charges.

If the over due days is 7 it should calculate 0.3%

if over due days between 8 and 13 it shouldn't calculate any thing until it reach 14 days to calculate anther 3% .

I made the setup and the system is calculating the late charges . My issue is that it calculate the 3% even the over due days is one day and also it calculate it on daily basis ( calculate 3%  for each run on daily basis)

I tried different