Using glow wrong?

M
Hi everyone! 
My husband and I are not TTC but I have my glow set to TTC because I feel it gives me the most accurate readings on when to be extra careful. We are doing NFP as a form of birth control. So far successful for 8 months, keeping my fingers crossed real tight, although babies are always a blessing. 
Does anyone else agree with me or was I using glow wrong? There's no percentages when you tell glow you're not trying to conceive right?