Jim I am just like you. I have a wine fridge and my herpstat said 89.9 and the egg box temps have been right at 88.5-88.9. That was before I got my first clutch this year.

Then I added my clutch of 3 eggs and the temps rose right up to the 89.9. So I adjusted accordingly and had the tstat set to 88.9 and the eggs boxs @ 88.5.

Get this... This morning I wake up and the eggbox temp according to my accurite was 87.6.... Talk about driving me nuts.... LOL Either the accurite is going bad or I am going insane... Because the herpstat was right at 88.9... I think I am going to just follow my herpstat...