ATIS STATES THAT TWR IS CLOSED FOR NIGHT. ACFT TAXI'S OUT WITHOUT CONTACTING TWR ONLY TO FIND THAT TWR IS STILL OPEN.

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IN PREPARATION FOR DEP; I (PIC) WAS PNF; PICKED UP ATIS. ATIS STATED; '...JACKSON TWR HAS SUSPENDED OPS. TAS ON 120.7...' I ANNOUNCED TAXI INTENTIONS FROM THE RAMP TO RWY 24 AND PF (A CFI) BEGAN THE TAXI. UPON REACHING CTR TAXIWAY; TWR CALLED MY ACFT AND ASKED INTENTIONS; STATING TWR WOULD BE CLOSING SHORTLY. I REPLIED THAT WE WERE INTENDING TO DEPART RWY 24 AND HAD LEARNED FROM ATIS THAT TWR WAS CLOSED. TWR RESPONDED THAT THEY WERE INDEED IN OP; AND WE WERE NOT THE FIRST TO BE CONFUSED BY THE ATIS. CONTRIBUTING FACTORS: ATIS SPECIFICALLY STATED TWR HAD SUSPENDED OPS. WE ANNOUNCED TAXI ON CTAF WHICH WAS TWR FREQ. TWR DID NOT; UPON OUR BROADCAST; ACKNOWLEDGE THE XMISSION NOR INFORM US THEY WERE OPERATING. OUR PHRASEOLOGY WAS STANDARD UNCTLED FIELD TERMINOLOGY 'JACKSON TFC; N... RAMP TAXI TKOF RWY 24 JACKSON.' DISCOVERY: JXN TWR CALLED US AFTER WE WERE 2/3 WAY TO RWY TO ASK OUR INTENTIONS. ATC PROBABLY SHOULD NOT TURN ON LAST ATIS UNTIL ACTUALLY CLOSED. BELIEVE IT OR NOT; SOME OF US ACTUALLY DO LISTEN BEFORE TAXI/ARRS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO. ANALYST HAD QUESTIONS WITH INCIDENT DATES NOT MATCHING ON BOTH RPTS. RPTR STATES THAT THE SECONDARY RPT DATE IS CORRECT. RPTR ALSO CONTACTED TWR MGR AND REVIEWED ATIS CONFUSION. SUPPOSEDLY THE MGR IS LOOKING INTO IT. CALL TO FACILITY REVEALED THAT ATIS IS BROADCAST 5-10 MINS BEFORE THE CTLR CLOSES THE TWR; HOWEVER; THERE IS A CLOSING AND OPENING TIME ALSO INCLUDED IN THE ATIS. IN THIS CASE THE TWR CLOSES AT 2100 AND OPENS AT 0600; WHICH WAS ON THE ATIS WHEN INCIDENT OCCURRED. APPARENTLY; THE RPTRS DID NOT HEAR THE TIMES STATED. SUPPLEMENTAL INFO FROM ACN 219767. WE MONITORED ATIS; WHICH STATED THAT ATC SVCS HAD BEEN SUSPENDED AT 9 PM. TWR INDICATED THAT THEY PUT THIS FINAL ATIS AT 5-10 MINS EARLY; THAT THIS HAD CAUSED CONFUSION BEFORE WITH OTHER PLTS; AND THAT THE FACILITY PROBABLY SHOULD INTERNALLY DISCUSS THIS POLICY.