diff --git a/product_pricelist_total_margin/README.md b/product_pricelist_total_margin/README.md
index bf220a9..79a47e4 100644
--- a/product_pricelist_total_margin/README.md
+++ b/product_pricelist_total_margin/README.md
@@ -22,20 +22,36 @@ Pricelist B: 25% markup → 4.446 × 1.25 = 5.5575€
 
 With this module, you can calculate the **total margin** by summing percentages:
 
+#### Option 1: Markup (on cost)
 ```
 Base price: 4.68€
 Total margin: -5% + 25% = 20%
 Final price: 4.68 × 1.20 = 5.616€
+Effective margin: (5.616 - 4.68) / 5.616 = 16.67%
 ```
 
-**Result:** 5.62€ (effective margin: 20%)
+**Result:** 5.62€ (20% markup on cost)
+
+#### Option 2: Commercial Margin (on PVP)
+```
+Base price: 4.68€
+Total margin: -5% + 25% = 20%
+Final price: 4.68 / 0.80 = 5.85€
+Effective margin: (5.85 - 4.68) / 5.85 = 20%
+```
+
+**Result:** 5.85€ (20% commercial margin on PVP)
 
 ## Features
 
 - ✅ **Additive margin calculation** across chained pricelists
+- ✅ **Two calculation methods:**
+  - **Markup (on cost):** `PVP = Cost × (1 + markup%)`
+  - **Commercial Margin (on PVP):** `PVP = Cost / (1 - margin%)`
 - ✅ **Opt-in via checkbox** - doesn't affect existing pricelists
 - ✅ **Compatible with custom bases** (`last_purchase_price` from `product_sale_price_from_pricelist`)
 - ✅ **Supports all formula extras** (price_round, price_surcharge, price_min/max_margin)
+- ✅ **Global min/max margin limits** (configurable in Settings > Sales)
 - ✅ **Multi-level chains** - works with 2+ pricelists in sequence
 - ✅ **Currency conversion** - handles multi-currency scenarios
 - ✅ **Detailed logging** - debug pricing calculations easily
@@ -84,7 +100,10 @@ Create a pricelist that chains to the base one:
    - **Based on:** Other Pricelist → Select "Base Pricelist - Last Purchase Price"
    - **Price Computation:** Formula
    - **Discount:** -25% (negative = 25% markup)
-   - **☑️ Use Total Margin:** Check this box!
+   - **☑️ Total Margin Mode:** Check this box!
+   - **Calculation Method:** Choose between:
+     - **Markup (on cost)** - Default, calculates `PVP = Cost × (1 + markup%)`
+     - **Commercial Margin (on PVP)** - Calculates `PVP = Cost / (1 - margin%)`
 
 ### Step 3: Assign to Products
 
@@ -113,19 +132,38 @@ After product category (+25%): 5.5575€ ❌ Wrong effective margin: 18.8%
 Product: Flour (cesta básica, repostería)
 Purchase price: 4.68€
 Total margin: -5% + 25% = 20%
-Final price: 5.616€ ✅ Correct effective margin: 20%
+
+Option 1 - Markup:
+  Final price: 4.68 × 1.20 = 5.616€ ✅ Markup 20% on cost
+
+Option 2 - Commercial Margin:
+  Final price: 4.68 / 0.80 = 5.85€ ✅ Margin 20% on PVP
 ```
 
+**Which method to choose?**
+- **Markup (on cost):** Traditional markup calculation, margin on cost base
+- **Commercial Margin (on PVP):** Retail/commercial margin, ensures exact margin percentage on final price
+
 ## Technical Details
 
-### New Field
+### New Fields
 
 - **Model:** `product.pricelist.item`
-- **Field:** `use_total_margin` (Boolean)
+
+#### `use_total_margin` (Boolean)
 - **Default:** False (opt-in)
 - **Visibility:** Only shown when:
   - `compute_price = 'formula'`
   - `base = 'pricelist'` (chained pricelist)
+- **Purpose:** Enable additive margin calculation instead of compound
+
+#### `margin_type` (Selection)
+- **Default:** `'markup'`
+- **Options:**
+  - `'markup'` - Markup (on cost): `PVP = Cost × (1 + markup%)`
+  - `'margin'` - Commercial Margin (on PVP): `PVP = Cost / (1 - margin%)`
+- **Visibility:** Only shown when `use_total_margin = True`
+- **Purpose:** Choose the calculation method for the total margin
 
 ### Methods
 
@@ -159,9 +197,14 @@ Main override that:
 1. Checks if `use_total_margin=True` and conditions are met
 2. Calls helper methods to get base price and margins
 3. Sums margins additively: `total_margin = sum(margins)`
-4. Applies total margin: `price = base_price * (1 + total_margin / 100)`
-5. Applies formula extras
-6. Falls back to standard behavior if conditions not met
+4. Applies global min/max margin limits if configured
+5. Applies total margin using selected method:
+   - **Markup:** `price = base_price * (1 + total_margin / 100)`
+   - **Commercial Margin:** `price = base_price / (1 - total_margin / 100)`
+6. Applies formula extras
+7. Falls back to standard behavior if conditions not met
+
+**Safety:** Commercial margin >= 100% is capped at 99% to avoid division by zero
 
 ### Logging
 
@@ -170,7 +213,12 @@ All calculations are logged with `[TOTAL MARGIN]` prefix for easy debugging:
 ```python
 _logger.info("[TOTAL MARGIN] Item %s: base=%s, margin=%.2f%%", ...)
 _logger.info("[TOTAL MARGIN] Margins: ['5.0%', '25.0%'] = 20.0% total")
-_logger.info("[TOTAL MARGIN] Base price 4.68 * (1 + 20.0%) = 5.616")
+
+# Markup method:
+_logger.info("[TOTAL MARGIN] Markup: Base 4.68 * (1 + 20.0%) = 5.616")
+
+# Commercial Margin method:
+_logger.info("[TOTAL MARGIN] Commercial Margin: Base 4.68 / (1 - 20.0%) = 5.85")
 ```
 
 View logs:
@@ -189,12 +237,16 @@ docker-compose run odoo odoo -d odoo --test-enable --stop-after-init -u product_
 ### Test Coverage
 
 - ✅ Compound margin (default behavior preserved)
-- ✅ Total margin (additive calculation)
+- ✅ Total margin with Markup calculation
+- ✅ Total margin with Commercial Margin calculation
 - ✅ Formula extras (round, surcharge, min/max)
+- ✅ Global min/max margin limits
 - ✅ 3-level pricelist chains
 - ✅ Different base types (last_purchase_price, list_price)
 - ✅ Currency conversions
 
+**Total:** 11 tests, all passing
+
 ## Compatibility
 
 - **Odoo Version:** 18.0
@@ -271,10 +323,21 @@ AGPL-3.0 or later
 
 ## Changelog
 
+### 18.0.1.1.0 (2026-02-21)
+
+- **[IMP]** Add `margin_type` field to choose between calculation methods
+  - **Markup (on cost):** `PVP = Cost × (1 + markup%)`
+  - **Commercial Margin (on PVP):** `PVP = Cost / (1 - margin%)`
+- Add 2 new tests for both calculation methods
+- Add safety cap for commercial margin >= 100% (caps at 99%)
+- Improve logging to show which calculation method is used
+- Total: 11 tests passing
+
 ### 18.0.1.0.0 (2026-02-21)
 
 - Initial implementation
 - Support for additive margin calculation in chained pricelists
 - Compatible with `last_purchase_price` custom base
-- Comprehensive test suite
+- Global min/max margin limits configuration
+- Comprehensive test suite (9 tests)
 - Detailed logging for debugging
diff --git a/product_pricelist_total_margin/__manifest__.py b/product_pricelist_total_margin/__manifest__.py
index 4f714db..8003703 100644
--- a/product_pricelist_total_margin/__manifest__.py
+++ b/product_pricelist_total_margin/__manifest__.py
@@ -2,9 +2,9 @@
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
 {  # noqa: B018
     "name": "Product Pricelist Total Margin",
-    "version": "18.0.1.0.0",
+    "version": "18.0.1.1.0",
     "category": "Sales/Products",
-    "summary": "Calculate total margin additively instead of compounding in chained pricelists",
+    "summary": "Calculate total margin additively with Markup or Commercial Margin methods",
     "author": "Odoo Community Association (OCA), Criptomart",
     "website": "https://git.criptomart.net/criptomart/addons-cm",
     "license": "AGPL-3",