# Margin and Tier Guidelines (Skincare Quantity Breaks)

Quick reference for the tiered-quantity-discounts-skincare skill. Load when the agent needs margin math or copy patterns without re-reading the full SKILL.

## Contents

- [Margin impact (percentage-off tiers)](#margin-impact-percentage-off-tiers)
- [Typical tier shapes (skincare)](#typical-tier-shapes-skincare)
- [Copy patterns (EN)](#copy-patterns-en)
- [Scope](#scope)

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## Margin impact (percentage-off tiers)

If list price is **P** and gross margin at full price is **M%** (e.g. 60%):

- **1 unit**: margin = M%
- **2 units @ 10% off**: effective price = 0.9P each → effective margin ≈ M% − (discount impact on margin). Rough rule: 10% off often reduces margin by ~10% of the discount (e.g. 60% → ~54% if COGS is 40% of P).
- **3 units @ 15% off**: effective price = 0.85P each → margin drops further.

**Safe rule**: For a 60% gross margin product, 10% off keeps margin in the mid–high 50s; 15% off often lands in low–mid 50s. Always compute or state effective margin when proposing tiers.

## Typical tier shapes (skincare)

| Shape        | Example              | Use when                          |
|-------------|----------------------|-----------------------------------|
| 2 tiers     | 1 = full, 2+ = 10%  | Conservative; testing the mechanic |
| 3 tiers     | 1 / 2 @ 10% / 3+ @ 15% | Standard "buy more save more"   |
| Steeper     | 2 @ 10%, 3 @ 18%, 4 @ 22% | Strong stock-up push; need margin headroom |

## Copy patterns (EN)

- PDP: "Buy 2, save 10% — Buy 3, save 15%."
- Cart: "You're saving 10% on this item (buy 2+)."
- Banner: "Stock up and save: 10% off 2, 15% off 3+ on serums and moisturizers."

## Scope

- **Single hero product**: Tiers on one SKU (e.g. hero serum).
- **Category**: All serums, or all moisturizers.
- **Full range**: Entire skincare catalog (ensure margin is consistent across products).

Use this file when the agent needs to double-check margin math or copy patterns without re-reading the full SKILL.