If you're hitting odd delays you'll ONLY hit odd delays, so you were doing something wrong. Ideally you should have chosen a seed with an odd delay to match yours. You can do one of the 3 things suggested above...i have a ds lite but not gen 3 pokemon games. i have other gba games if those would work. my target delay is 518 and i keep getting 517, 519, 523, etc. i adjust the pikatimer accordingly, but then i WOULD'VE gotten 518 on some occasions. i have yet to try changing the year or inserting gba or moving the arrow down since i'm on SS.
-change the year by 1 (will change your delay by 1 so it'll be odd)
-insert the gba game
-the up/down on the continue screen
personally I've never done the latter 2