Is it common to have two different results on ovulation tests? I've been using the clear blue tests for only a few days. The regular digital test is still saying low fertility while the advanced test went from low fertility to peak. I'm not sure which one is correct. I'm on cycle day 9 and my cycle is always between 27-28 days and the app didn't have ovulation occurring until the 20th. Any help would be appreciated. Thanks!