Putaway suggestion to Overflow location

Hi!

There is a request to putaway a quantity of 2 boxes, the instruction is to putaway in a fixed location. The location is not full, there still space available but WMS see that the location is full and the suggestions is to putaway into the overflow (O) location. The capacity method is setup at 2. When i look to the location utilisation the volume is for 2 entire pallet but there is only a pallet and a half in the location.

Why the utilized volume seams to only look at the pallet dimension?

Thanks,