Hi,
Yes, that’s correct. This is exactly how “Per product category” option is working in our plugin.
Maybe one small note. You wrote:
“If user A purchased 4 Product A1, user A can still buy 1 Product from either Product A2, Product A3, Product A4.”
To be exactly correct, it should be:
“If user A purchased 4 Product A1, user A can still buy 1 Product from either Product A1, Product A2, Product A3, Product A4.”
i.e. he can still buy 1 x “Product A1” as well.
Hope that helps. Please let me know if you have any questions.