Combining Operations with gaps

Dears,

Reference to the following link it says that it's not allowed to combine operation with gaps, for example if a routing consists of the operations 10, 20, and 30, you cannot combine operations 10 and 30 without operation 20.

Selecting Operations - SAP Mill Products - SAP Library

I need to know why this is mandatory and if there are any way to overcome this

Thanks in Advance,

Best Regards,

Keroles Abader