I don't think increasing PKCe levels are what's directly causing the improving SIB scores.
From what I can tell based on the research articles (and all the charts showing consistent PKCe levels), it's more that Bryostatin brings PKCe levels back to normal, which enables the brain to properly engage its own repair mechanisms again.
A normal human brain constantly repairs itself and clears out anything bad throughout its lifespan (For example, researchers think that the reason we have to sleep is because the brain uses that time to clear itself of toxins that have accumulated during the day), but Alzheimer's somehow blocks that mechanism (because of too low PKCe levels probably) and causes the brain to deteriorate over the span of several years.