i expect the result is 530,and define the "no-loop=true" in the rules ,but result is 460,why?

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my java test code:

package org.sample;

import org.drools.KnowledgeBase;
import org.drools.KnowledgeBaseFactory;
import org.drools.builder.KnowledgeBuilder;
import org.drools.builder.KnowledgeBuilderError;
import org.drools.builder.KnowledgeBuilderErrors;
import org.drools.builder.KnowledgeBuilderFactory;
import org.drools.builder.ResourceType;
import org.drools.io.ResourceFactory;
import org.drools.logger.KnowledgeRuntimeLogger;
import org.drools.logger.KnowledgeRuntimeLoggerFactory;
import org.drools.runtime.StatefulKnowledgeSession;

public class SalesTest {

public static final void main(String[] args) {
  try {
   // load up the knowledge base
   KnowledgeBase kbase = readKnowledgeBase();
   StatefulKnowledgeSession ksession = kbase.newStatefulKnowledgeSession();
   KnowledgeRuntimeLogger logger = KnowledgeRuntimeLoggerFactory.newFileLogger(ksession, "test");
   // go !
   Sales message = new Sales();
   message.setName("sinboy");
   message.setSales(600);
   ksession.insert(message);
   ksession.fireAllRules();
   //ksession.dispose();

   System.out.println("updated:"+message.getName()+","+message.getSales());
   logger.close();
  } catch (Throwable t) {
   t.printStackTrace();
  }
}

private static KnowledgeBase readKnowledgeBase() throws Exception {
  KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();
  //kbuilder.add(ResourceFactory.newClassPathResource("Sample.drl"), ResourceType.DRL);
  kbuilder.add(ResourceFactory.newUrlResource(" http://127.0.0.1:8080/drools-guvnor/org.drools.guvnor.Guvnor/package/org.sample/LATEST"), ResourceType.PKG);
  KnowledgeBuilderErrors errors = kbuilder.getErrors();
  if (errors.size() > 0) {
   for (KnowledgeBuilderError error: errors) {
    System.err.println(error);
   }
   throw new IllegalArgumentException("Could not parse knowledge.");
  }
  KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase();
  kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());
  return kbase;
}

}

the print info is:

fired1:discount,550
fired0:discount,530
fired1:discount,480
fired0:discount,460
updated:discount,460

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my java model is :

package org.sample;

import java.util.Date;

public class Sales {
private String name;
private long sales;
private Date dateOfSale;
private boolean chocolateOnlyCustomer;

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public long getSales() {
return sales;
}

public void setSales(long sales) {
this.sales = sales;
}

public Date getDateOfSale() {
return dateOfSale;
}

public void setDateOfSale(Date dateOfSale) {
this.dateOfSale = dateOfSale;
}

public boolean isChocolateOnlyCustomer() {
return chocolateOnlyCustomer;
}

public void setChocolateOnlyCustomer(boolean choclateOnlyCustomer) {
this.chocolateOnlyCustomer = chocolateOnlyCustomer;
}
}

rules:

dialect "mvel"
no-loop true

rule "DiscountRule"
   salience 9
when
      $fact0:Sales(s:sales>100)
then
      #Sales fact0=new Sales();
      #fact0.setSales(s.getSales()-10);
      #fact0.setName("discount");
      #insert(fact0);

      modify($fact0){setName("discount")}
      modify($fact0){setSales(s-20)}
      System.out.println("fired0:"+$fact0.getName()+
                                ","+$fact0.getSales());
end

rule "DiscountRule2"
   salience 18
when
      $fact1:Sales(s1:sales>500)
then
      modify($fact1){setName("discount")}
      modify($fact1){setSales(s1-50)}
      System.out.println("fired1:"+$fact1.getName()+
                                ","+$fact1.getSales());
end