ACR FLC ALTDEV RESULTED FROM MISCOM BTWN FLC AND ATC.

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DEPARTED GRAND RAPIDS; HANDED OVER TO ZAU CLRED DIRECT TO FWA VORTAC TO CLB TO AND MAINTAIN FL190. REACHING FL190 WE HEARD THE CTLR CLR SOMEONE TO FL230 BUT WE DID NOT HEAR A CALL SIGN. A FEW MOMENTS LATER; WE WERE INSTRUCTED TO TURN R 20 DEGS FOR OUR CLB. MY FO ACKNOWLEDGED THIS STATING 'TURNING R TO 210 DEGS CLBING TO FL230 CALL SIGN.' AT FL203; THE CTLR STATED 'CALL SIGN I DID NOT CLR YOU TO CLB OUT OF FL190.' I IMMEDIATELY TERMINATED THE CLB AND BEGAN TO DSND BACK TO FL190. MOMENTS LATER; THE SAME CTLR CLRED US TO CLB TO FL230. A FOLLOW UP PHONE CALL TO THE CTLR AND THE SUPVR CLRED UP SOME OF THIS MYSTERY. THE CTLR SAID THE SECTOR WAS IN THE PROCESS OF BEING SPLIT WHEN WE CHKED IN. THE CTLR WAS SIMULCASTING ON 2 DIFFERENT FREQS. THE CLRNC TO CLB WAS TO ANOTHER ACFT THAT WAS IN ANOTHER SECTOR BEYOND THE 40 MI RANGE OF OUR TCASII SUPPLEMENTAL INFO FROM ACN 306072: AFTER CHK- IN; WE HEARD A CALL TO CLB AND MAINTAIN FL230 BUT WE WERE UNSURE OF THE CALL SIGN. WHEN WE DIDN'T HEAR ANYONE ELSE RESPONSE -- WE RESPONDED BY SAYING 'CLRED TO FL230; CALL SIGN.' THERE WAS NO IMMEDIATE RESPONSE BUT MOMENTS LATER WE RECEIVED A CALL FROM CTR STATING; 'CALL SIGN TURN R 20 DEGS FOR YOUR CLB.' WE WERE UNDER THE IMPRESSION THAT WE WERE THE ONLY ACFT HE WAS IN CONTACT WITH.