You’re right. It works worrectly in “Normal” mode but not in “Cumulative” mode. I’ll check what’s going on and update the plugin as soon as possible, do you have the possibility to switch to “Normal” mode?
No it’s not planned, as Easy Booking is used for a lot of different things (like equipemenet renting, etc.) that don’t require to select a number of people. I think you can use WooCommerce Product Addons in order to achieve this (it’s installed on the demo if you want to try).