Designing all PCBs on one board and then Separate them using CNC 3018 pro?

I design a lot of prototype PCBs and send them to JLCPCB, but sometimes I get charged for multiple designs on the same board because of the weird board outline (I make the board outline in such a way that I can cut it easily). So, I was thinking of just making the board outline as a normal square PCB and using CNC 3018 pro to cut these PCBs at home. what do you think of that?