Magento

Hello,
I set 150 as maximum allowed weight per package.
Now I was on call with FedEX to check how the request is sent at there end.
If I have cart weight below 150lbs the FedEX server gets correct weight on there server.
Now if I have more that 150lbs in my cart FedEx agent told me that they only got 120lbs on there server and as one 1package.

Now here is the problem, In Magento If I enter any weight in cart it always take it as 1 package.
and if I add more that 150lbs in my cart it still take it as 1 package with around 122-125lbs and rejects rest of the weight.
its not making multiple packages if my weight is more than 150lbs as it works on FedEx desktop tool.

Any help??

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