Flat Rate plus its additional per kg rate config -- urgently

Hi there…



I’m very baffled at how to setup the Flat rate for EMS / Fedex Saver boxes plus their Additional per kg rate.



Was told to set it up this way



Per Items

0 pcs = $50.80 (base rate for 5kg)

25 pcs = $1.33



Per kg Additional rate = $6.65



However the system seems to take $1.33 * number of pcs in total – ie for 30 pcs becomes $1.33 * 30 = $39.90, which is not correct as I have a base rate… and $50.80 is supposed to add on to $1.33 * 5 : $6.65 – total 30 pcs ($57.45 as shipping total).



for 40 pcs – $50.80 + $1.33 * 15 = $70.75 (8 kg as per add on from the $6.65 per kg rate from 5 kg onwards)



Base rate for is for 5 kg – 25 pcs of games (0.2 kg each), 10 kg - 50 pcs, 20 kg - 100 pcs of games.



Could you enlighten in additional how to do this? Do not want to do data entry the long way… need a simple yet quick method to enter this.





Thank you.



Regards



Faustine