Yes, that is right. As the year increase, the delay decreases (excuse me for saying target delay, I meant change your actual delay, as targets are universal and static within the games, lol). Right, right.
However, if you are hitting an odd delay of 603, add those years and fix that GBA slot to get an even delay...
If a GBA game has been inserted all this time, now take it out.
If your GBA slot has been empty all this time, insert a game. ^^