When to test - ovulation differs to apps?

Amy
I know this sounds such a daft question!
I have been using ovulation a strips along with glow and many other tracking apps
 
The ovulation sticks tested positive 4 days after the apps predicted I would ovulate 
So I gather my period would be due later would it be 4 days later? I was due yesterday with the apps but I'm thinking that's probably not accurate?
Any advice approciated xx