Screenwriting : Copyrighting After a Rewrite by Frank Wood

After copyrighting one's screenplay, must he pay the hundred-dollar upgrade fee for each rewrite of the same title? The initial fee is thirty-five dollars, but any changes thereafter to the same title cost a C-note. With my first script, I knew there would be rewrites, so I changed the title each time (adding 01, 02, 03 etc.) so each would cost only thirty-five dollars. But, I wondered if these suffixes to the title would weaken my protection or if all this trouble was even necessary. My idea was to omit the suffix if the script were ever "locked". Now, I have another completed project and one in the batter's box. I thought I'd run this question through Stage 32 before proceeding with the copyrights on them.