There is a special and not so obvious settings in the planning profile which allows to set optimizer penalty costs for different loading levels of a truck.
Let´s take the example of a minimum usage of a truck of 38.000 lb which is ~84,44444444444% of 45.000 lb.
In the cost profile you can assign a cost function for ONE dimension (this is a limitation here) for a means of transport.
In the example I don´t want to use resources of Means of transport 0001 if the load is below 38.000lb.
The tricky part is that the dimension for the MTR is defined in the planning cost profile and the actual values for the cost function in the cost function profile. The advantage is the reuse for multiple MTRs (and even multiple dimensions, if this makes sense…)
Some more info can be found here: