Look at RNG Reporter while you do the guides. If you don't see an option for plus or minus seconds on the window you are using, then chances are you're not on the right option. Usually, you find plus and minus seconds when looking for adjacent delays. This is either generated by a right click on the seed you got in Time Finder, or you find it in Seeds to Time in the lower section.
I'll go fix the guide so it says +/-. That may help.