My kids with high WMI/PSI seem to learn without much practice or effort. I remember multiplication as happening with a conversation about what it meant and then I could literally say what is 8x8 and the 4 yo could respond with the right answer. Is that LOG? Is that a kid who could skip count so fast that it was like memorizing times tables? Or is it a kid who is "mathy" and just seemed to get numbers? But those kids also "get" reading and abstract thought and most things . . . . .

. For my child with normal PSI and WMI,
it's a difference of effort and repetition necessary for learning. Although abstract thought and incredible insight comes pretty easily, computation, reading and spelling have required effort and learning over time.
Hi G3 ((waving wildly))
I haven't read this whole thread yet, so appologies if I'm repeating, but here's my take.
Folks (like me) with more average Working Memory, need to practice, practice, practice so that the information they are handling is truly into long term memory, and nice and compact so that it takes up less room when being used by the working memory. An example of this is how when one is at a new workplace, it takes a while before the routines are 'down' enough that one doesn't have to look up their boss's extention every single time, and then complicated tasks can be done more rapidly and easily.
Folks (like me) with super-fast processing speed, may be moving stuff into Long Term memory in what looks like an instant to an outsider. My example of this was sitting in high school classrooms and opening up my ears and just by consentrating I could 'hear the material' and 'relate it to what it already knew' and 'file it well enough that I wouldn't have to study for the test' IF the topic was interesting and abstract enough, such as English, and sometimes history. Of course with History I'd have to go back and memorize the relavant dates and names, but getting the main point was shipped directly to Long Term Parking while the lecture was going on.
Of course, teaching multiplication when it was hard enough to be fun was probably also a very good thing. One of DS's teachers said to me once: 'When stuff is so easy to learn, one doesn't have to put much attention on it while learning, and is more at risk for forgetting.' My hunch is that your 4 year old was quite fasinated by '8x8' at the time, and might have appeared to need more drill if they tried to learn this for the first time in 3rd grade.
Does this make sense with what you are seeing?
Love and More Love,
Grinity