PA28-161 FLT INSTRUCTOR AFTER LNDG AND HAVING TRAINEE'S CHANGE SEATS; RPTR WAS IN COM WITH TWR; BUT APPARENTLY TWR WAS UNSURE OF THEIR POS. NO CONFLICTS.

Narrative

I WAS FLYING WITH 2 STUDENTS FOR THEIR NIGHT CURRENCY. WE DID 2 STOP-AND-GOES FOLLOWED BY A FULL STOP WITH THE FIRST STUDENT. AS WE CLRED THE RWY; TWR ASKED IF WE WANTED TO TAXI BACK TO THE RAMP. WE REPLIED; 'NO; WE WOULD LIKE TO TAXI BACK TO RWY 9L FOR MORE LNDGS AFTER WE MAKE A QUICK SEAT CHANGE?' THE TWR REPLIED; 'ROGER; CONTACT ME WHEN YOU ARE READY.' WE THEN CHANGED SEATS AND BEGAN TO TAXI BACK TO THE RWY. TWR COULD NOT SEE US; BUT WARNED US TO WATCH FOR A CESSNA WHO WAS GOING TO BACK- TAXI RWY 9L TO THE RAMP. TWR THEN SAID HE DID NOT KNOW WHERE WE WERE. WE THEN TURNED OUR LNDG LIGHT ON TO HELP HIM FIND US. WHEN WE GOT TO THE END OF THE RWY WE INFORMED TWR WE WERE READY. TWR CLRED US FOR TKOF AND WE COMPLETED THE FLT UNEVENTFULLY. WHEN TWR ASKED WHERE WE WERE IT HIT ME THAT MAYBE THEY WANTED US TO CALL BEFORE PROCEEDING WITH OUR TAXI. I AM STILL NOT SURE WHAT THE CTLR WAS TELLING US WHEN HE SAID TO CONTACT HIM WHEN READY (READY FOR TKOF OR READY TO TAXI AFTER THE SEAT CHANGE). IN THE FUTURE; I WILL TRY AND RECOGNIZE POOR COM AND TRY TO CLARIFY IT.