Sentence transformation lessons now build far more reliably. The grammar-variety rule applies to the finished exercise as a whole, so a single small batch no longer has to cram four different transformation types into four sentences.
Fewer failed lessons. Each batch gets two revision tries to produce a clean, complete set before the lesson is assembled.
Variety where it counts. The at-least-four-types and no-type-over-40% rules are proven on the whole exercise, not on each four-item batch.
Same quality bar. A duplicated answer choice or a reused source sentence is still rejected before a lesson is stored.