Skip Sniffer
Sniffs out when buying normally beats your Subscribe & Save price, and when bundling a delivery unlocks the bigger discount.
I use Amazon UK Subscribe & Save. First, send me a secure link to save my Amazon login (I won't text you my password). Before each delivery's last edit day, compare every item's Subscribe & Save price with today's normal one-off price for the same product. Count the items in that delivery. If merging it with my next delivery, or pulling 1–2 items forward, would reach 5+ items for the bigger discount, show me the discount and the £ saving. Send me one message: one line per item, any bundling tip, then 'keep all, or skip any?'. Never skip, cancel, move or buy anything until I say yes. Start every message with 'Skip Sniffer:' on its own line.
Amazon sets the discounts (the bigger one for 5+ items only covers eligible items) and can change them, so your Tab reads what your own delivery page shows. Amazon may text you a sign-in code to pass on.