Airport starts up with Internet status instead of computer-to-computer status

I only use my Mac's built-in Airport to use my work Windows laptop to connect to the internet. I must use my work PC and a VPN connection to internet for security reasons. To do this I create a network on my Mac which starts out with computer-to-computer status. I then start my work PC laptop, join the network to my Mac, and then I can connect by a VPN connection. When I'm finished using the network, I turn airport off. The next time I want to connect my work PC to the airport network, I turn on Airport and instead of a computer-to-computer status, it has an "internet sharing" icon. If my Mac displays this status icon, I can't connect to the PC to the internet. I must regenerate the network to get the computer-to-computer status every time.

I don't understand how all this is working, and I'm grateful to have discovered this workaround to enable me to connect to the internet on my work PC, but this seems like a very odd way to have to do this.

Can someone explain to me what is going on and how to make this easier?