Vetoing a Reasoning Model for a Live Autocomplete Feature

Product wants to add a reasoning model to a live code-autocomplete feature (suggestions must render within roughly 200ms to feel responsive) so that suggestions are "smarter about edge cases." The current standard-model setup already produces a usable suggestion in about 120ms and satisfies user feedback at a decent rate; the motivating complaint is a handful of cases where the current suggestion misses an edge case a more careful pass would have caught.

1. Make the case against using a reasoning model for this feature as specified, using this subject's decision framework explicitly (name the specific conditions that are violated).
2. The team still wants to address the underlying complaint (missed edge cases). Propose an alternative that doesn't require paying reasoning-model latency on the live path.
3. Under what different framing of the same underlying complaint would a reasoning model actually become the right tool?