When I look for shiny eggs, I typically look for low frames, not a frame of 1. I've found that as long as you hit your Initial Seed correctly and verify that the seed and delay are correct, the frames are usually correct (on rare occasions do undesired results occur).
The only time I've found the egg frames screwing up is when the date and time is very near the next day. Let's say, on the day 5/6/10, you find a good seed with a time of around 23:49, and you're looking for an egg on frame 3. If you do not get your third egg (frame 3) egg from the Daycare Man BEFORE the time reaches 00:00 (11 minutes later; signifying the next day 5/7/10), your egg will be a fail and the following eggs will all be random fails.
Make sure to note that they should pay attention to the time and date of the egg they're trying for. If the date changes before they get their egg, the egg will not be shiny. Also, low frames work just as well for the process, but your guide's noob-friendly so I guess that can be left in.