diff --git a/addons/product/product.py b/addons/product/product.py
index abdbcaf4895..69dc23b3fb6 100644
--- a/addons/product/product.py
+++ b/addons/product/product.py
@@ -178,10 +178,7 @@ class product_uom(osv.osv):
                 raise osv.except_osv(_('Error!'), _('Conversion from Product UoM %s to Default UoM %s is not possible as they both belong to different Category!.') % (from_unit.name,to_unit.name,))
             else:
                 return qty
-        # First round to the precision of the original unit, so that
-        # float representation errors do not bias the following ceil()
-        # e.g. with 1 / (1/12) we could get 12.0000048, ceiling to 13! 
-        amount = float_round(qty/from_unit.factor, precision_rounding=from_unit.rounding)
+        amount = qty/from_unit.factor
         if to_unit:
             amount = ceiling(amount * to_unit.factor, to_unit.rounding)
         return amount
diff --git a/addons/product/product_data.xml b/addons/product/product_data.xml
index 49362e380f4..4e62e1e0b3f 100644
--- a/addons/product/product_data.xml
+++ b/addons/product/product_data.xml
@@ -47,6 +47,7 @@
             <field name="category_id" ref="product_uom_categ_kgm"/>
             <field name="name">kg</field>
             <field name="factor" eval="1"/>
+            <field name="rounding" eval="0.001"/>
         </record>
         <record id="product_uom_gram" model="product.uom">
             <field name="category_id" ref="product_uom_categ_kgm"/>
diff --git a/addons/product/tests/test_uom.py b/addons/product/tests/test_uom.py
index 3d3ba04b689..e6ac6055137 100644
--- a/addons/product/tests/test_uom.py
+++ b/addons/product/tests/test_uom.py
@@ -12,7 +12,10 @@ class TestUom(TransactionCase):
     def test_10_conversion(self):
         cr, uid = self.cr, self.uid
         gram_id = self.imd.get_object_reference(cr, uid, 'product', 'product_uom_gram')[1]
+        kg_id = self.imd.get_object_reference(cr, uid, 'product', 'product_uom_kgm')[1]
         tonne_id = self.imd.get_object_reference(cr, uid, 'product', 'product_uom_ton')[1]
+        unit_id = self.imd.get_object_reference(cr, uid, 'product','product_uom_unit')[1]
+        dozen_id = self.imd.get_object_reference(cr, uid, 'product','product_uom_dozen')[1]
 
         qty = self.uom._compute_qty(cr, uid, gram_id, 1020000, tonne_id)
         self.assertEquals(qty, 1.02, "Converted quantity does not correspond.")
@@ -20,6 +23,20 @@ class TestUom(TransactionCase):
         price = self.uom._compute_price(cr, uid, gram_id, 2, tonne_id)
         self.assertEquals(price, 2000000.0, "Converted price does not correspond.")
 
+        # If the conversion factor for Dozens (1/12) is not stored with sufficient precision,
+        # the conversion of 1 Dozen into Units will give e.g. 12.00000000000047 Units
+        # and the Unit rounding will round that up to 13.
+        # This is a partial regression test for rev. 311c77bb, which is further improved
+        # by rev. fa2f7b86.
+        qty = self.uom._compute_qty(cr, uid, dozen_id, 1, unit_id)
+        self.assertEquals(qty, 12.0, "Converted quantity does not correspond.")
+
+        # Regression test for side-effect of commit 311c77bb - converting 1234 Grams
+        # into Kilograms should work even if grams are rounded to 1.
+        self.uom.write(cr, uid, gram_id, {'rounding': 1})
+        qty = self.uom._compute_qty(cr, uid, gram_id, 1234, kg_id)
+        self.assertEquals(qty, 1.234, "Converted quantity does not correspond.")
+
     def test_20_rounding(self):
         cr, uid = self.cr, self.uid
         unit_id = self.imd.get_object_reference(cr, uid, 'product', 'product_uom_unit')[1]