CBFM and OPK give different readings: which is right?

[Briss]

ladies I need a little help here, am so confused with my OPK and CBFM readings:

1. CBFM PEAK CD11-CD12

2. first response OPK positive CD13
(I did not test yesterday so could have been positive on CD12 as well but today I got both equally dark lines a few seconds after I POASed),

3. my other OPK positive on CD11-CD13
(I am actually not sure, Will try to attach a picture but it is not of great quality: first three sticks from the top are CD11, then two CD12 and last two CD13). Are they all look positive to you?

So my question is when did I have LH surge? who is right CBFM or First Response OPK? Temp is really of no help, it has gone up today cos I have a cold (also possible that I ovulated but hard to say)

 

[MaryP]

I would say cd13 seems positive! GL!

 

[Briss]

I would say cd13 seems positive! GL!

thank you I think you are right, I also got another positive today. still confused how come CBFM gave me a peak two days before OPK. BD today as well but still wonder which one is correct?