Prospects react to the sticker price in isolation and separately have no idea how long a bottle lasts or what ongoing costs look like together, this reads as "I don't know what I'm actually committing to."
Why it's powerful: Combines two clusters (Price Sticker Shock & Refill Math/Ongoing Cost Confusion) that are really the same underlying fear expressed at two different moments first at the price tag, then again at the refill question.
If we create ads that state the full cost picture upfront diffuser value, subscription price, and how long a bottle lasts, all in one place then we prevent the sticker-shock bounce, because this audience's objection isn't actually the price, it's not knowing what the total commitment looks like.