As it says in your post this is a series and not a single kind of weigela. What I've seen at outlets and in my own garden - I bought the white one soon after these came on the garden center market here - does not create the impression that there is much more of a follow up flowering than with certain other older, existing varieties. That is the general pattern seems to be a main spring bloom with some incidental flowering on new shoots later. So, on top of the individual flowers not being nearly as large I don't think you can count on these being any kind of visual replacement for Knockout series roses.