ROUTING CHANGE. ATC AND PLT MISCOM.

Narrative

I WAS ON AN IFR FLT FROM YUM TO SNA. PRIMARY ENRTE NAV EQUIP LORAN; FILED RTE OF FLT BZA; IPL; MZB THEN DIRECT; SNA. I OPTED FOR THIS UNUSUAL ROUTING BECAUSE OF CONVECTIVE ACTIVITY IN THE REGION OF JULIAN STRETCHING NEBOUND. AT ARR OVER IPL VOR IT WAS CLR THAT THE WX OVER JLI HAD MOVED NE OF OUR ROUTING. THE CTLR THEN CLRED ME 'DIRECT JLI; THEN REST OF RTE UNCHANGED.' IT WAS MY ASSUMPTION THEN THAT AFTER JULIAN VOR I WAS CLRED DIRECT TO SNA AFTER JLI VOR. UPON ARRIVING OVER JLI VOR I SELECTED DIRECT SNA AND PROCEEDED ACCORDINGLY. AFTER 9 MI PAST JLI VOR THE CTLR THEN REQUESTED I CROSS 10 MI E OF OCN AT 12000 FT. BY NOW I WAS PROCEEDING DIRECT SNA AND THE CTLR WAS STATING THAT I PROCEED VIA OCN. MY INITIAL CLRNC WAS MZB DIRECT SNA. WHEN I WAS CLRED JLI; REST OF RTE UNCHANGED I ASSUMED JLI DIRECT SNA. I MADE A RADICAL HDG CHANGE OF 060 DEGS TO KEEP ME CLR OF THE UPCOMING CAMP PENDLETON RESTR AIRSPACE. THE CTLR BECAME CONCERNED THAT I WAS UNSURE OF MY POS. AT THIS TIME I WAS TRYING TO IDENT OCN VOR IN THE LORAN; AS WELL AS FLY THE ACFT. I RECOMMEND THAT WHEN A REVISED CLRNC IS ISSUED THE CTLR CLARIFY IN THIS INSTANCE WHEN LORAN; GPS OR INS ARE BEING USED. I MYSELF SHOULD HAVE ASKED FOR CLARIFICATION PRIOR TO ARRIVING AT JULIAN VOR.