This is why the test specification says to contact us if you exceed those values.
It is reasonable to expect certain devices (such as flow) may support the complete range of floating point values. If you are certain this is implemented correctly, your sensor must be able to handle the range allowed in the device. You will need to submit a Change Request on why this range is valid for your device when you submit the device. The CR is necessary since your device will not reject any upper or lower range value.
Reference the approved CR number in your product registration submission.