Conflict with two magento extension updating the grandtotal

I have a magento extension giving a credit point to the customer and I added a custom extension giving a custom discount to the customer. The problem is that when i use the custom extension the credit point one is not adding to the grand total.
My custom extension has the following config.xml

< ?xml version="1.0"?>


    
        0.1.0
    



    
        
            
                
                Ei_Creditpoint
                    singleton
                    HK_Customdiscount_Model_Observer
                    setDiscount
                
            
        
    

the credit point extension has the following config.xml

            < ?xml version="1.0"?>
            
                
                    
                        1.0.1
                    
                
                
                    
                        
                            standard
                            
                                Ei_Creditpoint
                                creditpoint
                            
                        
                    
                     
                        
                            
                                ei/creditpoint.xml
                            
                        
                    
                    
                        
                            
                                
                                    Ei_Creditpoint.csv
                                
                            
                        
                    
                
                
                    
                        
                            admin
                            
                                Ei_Creditpoint
                                creditpoint
                            
                        
                    
                
                
                    
                        
                            
                                ei/creditpoint.xml
                            
                        
                    
                    
                        
                            
                                
                                    Ei_Creditpoint.csv
                                
                            
                        
                    
                
                
                    
                                        
                            10/10
                            100/10
                            0
                            0
                              
                    
                
                
                    
                        
                            Ei_Creditpoint_Block
                        
                        
                            
                                Ei_Creditpoint_Block_Sales_Order_Totals
                            
                        
                        
                            
                                Ei_Creditpoint_RW_Adminhtml_Block_Sales_Order_Totals
                                Ei_Creditpoint_RW_Adminhtml_Block_Sales_Order_Invoice_Totals
                                Ei_Creditpoint_RW_Adminhtml_Block_Sales_Order_Creditmemo_Totals
                            
                        
                    
                    
                        
                            Ei_Creditpoint_Helper
                        
                    
                    
                     
                         
                             
                                 creditpoint/sales_quote_address_total_creditpoint
                                 set_custom_discount
                                 tax
                             
                         
                     
                     
                         
                             
                                 creditpoint/sales_order_total_invoice_creditpoint
                                 set_custom_discount
                                 tax
                             
                         
                     
                     
                         
                             
                                 creditpoint/sales_order_total_creditmemo_creditpoint
                                 set_custom_discount
                                 tax
                             
                         
                     
                
                
                        
                            
                                
                                    singleton
                                    creditpoint/observer
                                    deductCreditAmount
                                
                            
                        
                        
                            
                                
                                    singleton
                                    creditpoint/observer
                                    revertCreditPoints
                                
                            
                        
                        
                        
                                
                            creditpoint/observer
                                    updatePaypalTotal
                            
                        
                        
                        
                            
                                
                                    creditpoint/observer
                                    invoiceSaveAfter
                                
                            
                        
                    
                 
                        
                            
                                *
                            
                            
                                *
                            
                        
                    
                    
                        
                            
                                Credit Points Discount
                                creditpoint_amount
                                creditpoint/sales_pdf_creditpoint
                                7
                                0
                                650
                            
                        
                    
                    
                        
                            Ei_Creditpoint_Model
                            creditpoint_mysql4
                        
                        
                            Ei_Creditpoint_Adminhtml_Model
                        
                        
                            Ei_Creditpoint_Model_Mysql4
                            
                                
                                    customer_credit_point
Ei_Creditpoint Mage_Eav_Model_Entity_Setup core_setup core_write core_read