Hello Olivier. Yes, I also have a similar situation. You can register and create as many apps with the same account. When you login using your credentials a popup is showing you a list of the apps you created with that account and you can click to select the app you want to edit. Hope this helps you.
Did you already register 2 times with the same mail and password? If not, you just need to register again with your same email and psw to create your second app. Then when you logout you will see all your apps and you can select and login into that app you want. When I'm on the login page I see a list of the apps I already registered and a button in the bottom part "Use another account", do you have the same?