Well, if you're averaging about 685, you should be able to adjust the timer by about 25 delays to start hitting around your target delay. Also, cartridges can either hit even delays or odd delays. If you can stick a 3rd gen cartridge in the bottom slot of your DS, that will switch it from odd to even. If you can't do that, then change the year of your DS by 1 and that will also let you hit even delays.