Help With Query ,should I Belive Profiler ?

Hi ,
I have query executed 1000 times a day by application with diffrent values in where ... but profiler shows different duration each time
duration might be 100 milisecond ,but might be 140000 miliseconds !!!

what is a reason ? should I belive profiler ?

SELECT cust_calls.call_date , cust_calls.work_order_sap , cust_calls.call_type_code , cust_calls.call_status , cust_calls.ind_max_expense , cust_calls.chng_date , cust_calls.user_id , cust_calls.call_seq_no , cust_calls.loc_equip_seq_no , cust_calls.initial FROM cust_calls WHERE (
cust_calls.loc_equip_seq_no = 3780 ) --changes with each query
ORDER BY cust_calls.call_date DESC

execution plan

|--Index Seek(OBJECT ([price].[dbo].[cust_calls].[cust_calls2]), SEEK ([cust_calls].[loc_equip_seq_no]=Convert([@1])) ORDERED FORWARD)
--space used--
name rows reserved data index_size unused
cust_calls 205019 201544 KB 74776 KB 38256 KB 88512 KB

-- table structure
CREATE TABLE [cust_calls] (
[call_seq_no] [numeric](7, 0) NOT NULL ,
[manufacturer_code] [char] (6) COLLATE SQL_Latin1_General_CP1_CI_AI NULL ,
[in_charge_code] [char] (6) COLLATE SQL_Latin1_General_CP1_CI_AI NULL ,
[work_order_sap] [char] (7) COLLATE SQL_Latin1_General_CP1_CI_AI NULL ,
[loc_equip_seq_no] [numeric](7, 0) NOT NULL ,
[call_type_code] [char] (5) COLLATE SQL_Latin1_General_CP1_CI_AI NOT NULL ,
[syst_lang_code] [char] (3) COLLATE SQL_Latin1_General_CP1_CI_AI NULL ,
[maint_emp_code] [char] (8) COLLATE SQL_Latin1_General_CP1_CI_AI NULL ,
[expense_code] [char] (5) COLLATE SQL_Latin1_General_CP1_CI_AI NULL ,
[ind_max_expense] [char] (1) COLLATE SQL_Latin1_General_CP1_CI_AI NULL ,
[call_date] [datetime] NULL ,
[call_status] [char] (1) COLLATE SQL_Latin1_General_CP1_CI_AI NULL ,
[call_description] [text] COLLATE SQL_Latin1_General_CP1_CI_AI NULL ,
[chng_date] [datetime] NOT NULL ,
[user_id] [char] (8) COLLATE SQL_Latin1_General_CP1_CI_AI NOT NULL ,
[Invoice_number] [varchar] (10) COLLATE SQL_Latin1_General_CP1_CI_AI NULL ,
[invoice_date] [datetime] NULL ,
[invoice_amount] [numeric](9, 2) NULL ,
[invoice_note] [text] COLLATE SQL_Latin1_General_CP1_CI_AI NULL ,
[initial] [char] (4) COLLATE SQL_Latin1_General_CP1_CI_AI NULL ,
[call_date_update] [datetime] NULL ,
[call_logon_id_update] [char] (8) COLLATE SQL_Latin1_General_CP1_CI_AI NULL ,
[gl_code] [char] (6) COLLATE SQL_Latin1_General_CP1_CI_AI NULL ,
[ind_follow_up] [char] (1) COLLATE SQL_Latin1_General_CP1_CI_AI NULL ,
CONSTRAINT [PK__cust_calls__4EF38B7F] PRIMARY KEY CLUSTERED
(
[call_seq_no]
) WITH FILLFACTOR = 90 ON [PRIMARY] ,
CONSTRAINT [FK__cust_calls__call___601E1781] FOREIGN KEY
(
[call_type_code]
) REFERENCES [cust_call_type] (
[call_type_code]
),
CONSTRAINT [FK__cust_calls__expen__267B85D1] FOREIGN KEY
(
[expense_code]
) REFERENCES [cust_expense] (
[expense_code]
),
CONSTRAINT [FK__cust_calls__in_ch__73BAFBDA] FOREIGN KEY
(
[in_charge_code]
) REFERENCES [cust_in_charge_warranty] (
[in_charge_code]
),
CONSTRAINT [FK__cust_calls__maint__40FA71E3] FOREIGN KEY
(
[maint_emp_code]
) REFERENCES [cust_maintenance_employees] (
[maint_emp_code]
),
CONSTRAINT [FK__cust_calls__manuf__41EE961C] FOREIGN KEY
(
[manufacturer_code]
) REFERENCES [cust_manufacturer] (
[manufacturer_code]
),
CONSTRAINT [FK__cust_calls__syst___1B29CEB6] FOREIGN KEY
(
[syst_lang_code]
) REFERENCES [cust_system_lang] (
[syst_lang_code]
),
CONSTRAINT [FK_cust_calls_cust_GL_Code_Type] FOREIGN KEY
(
[gl_code]
) REFERENCES [cust_GL_Code_Type] (
[gl_code]
)
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
GO