Running out of Clean Passages for RC

Hello, I usually drill 2 reading passages a day using the 7sage virtual tutor to pick. I am now done with all my clean passages but when I go to "particular tags" I still have 128 clean passages left. Does that mean I need to start picking from that only if I'm to read passages I haven't read? Why can't 7sage just give me any of those passages to take?

Thanks!