CONFUSED???? Different Results with different holders.

So my last couple cycles my results have just been kind of weird like two cycles ago it went low to peak instanly, last cycle I had kept having peak days, I don't know if you should keep testing after you should peak I do, but i ended up with 6-8 Peak days until low fertility, and I started testing on cycle day 4 a little early on accdient so I thought that was way too early to be ovualting. BUT back to my story of today (that was just a little back story as to why I did what I did), So I have 4 test holders things, I made sure I have used them multiple times so this wouldn't be the first time.  I have 3 of the more basic advance digital then just one that actually connects to my phone.  Well two of more basic digtial advance say I am at my peak fertility and the other one and the one that connects to my phone say low feritlity.  Can someone explain this mystery to me, the one that connects to my ohone has been with me for months and months, maybe 6 or more, and I bought these other 3 and used them probably a half dozen time each before today.