Payload in Axis 5 & 6

Hi, I´am using Roboload for calculate the load in J6 an J5, but I would like understand the way that the software solve it.
I was looking for in the handbook and I found this ecuations. 

Ja5 =Load (Kg) x (( z(m)+0.2^0.35)^2 + L^2) + max (J0x,J0y) <= 250 kgm2. 

Ja6= Load (kg) x L^2 +J0z<=185 kgm2.

I did the calculations to compare with robotload. For J6 it was correct, manually and with robotload its same , but J5, I never get the output that robotload gets. 

Can you help to understand how is the calculation?
There are some example or note about that for clear it . 

thank you in advance for an answer. 
best regards