NOOOOOOOOOOOOOOOOO
Just lock them down. I'm sure you'll be very surprised and have chicks, but you'll also be really upset when you realize you almost threw them out.
I was thinking 108 was my highest spike, but looking back it was 118. Moust have been all night and I still had a great hatch.
Lockdown, breath, sit on hands, wait! And they can be days late too, so if you see nothing until day 25, don't be surprised about that either.