Confused and really need help with weights

[chrisbarbers]

I have several shipping modules loaded and all seem to suffer the same issue.

Now it may be me and as usual I'll keep digging and may find the answer and just come back here and provide an update, but so far my search has yielded no answer.

On all my shipping modules when I select say 4 bags of dog food at 15kgs each, I get very spurious results, e.g. I know 4 * 15 = 60, so why does osCMax tell me it is 25, I have the max weight per item configured to 30, and have set up zone rates to be 30:7.95,60:15.90,90:23.85,120:31.80, so I am expecting a result of 16.90 which includes 1.00 for handling, the tare weight is set to 0.

What I get is £8.95 which is correct for 25

So where is this weight calculated as it seems to be miscalculating somehwere?

Any and all help greatfully appreciated.