Keep in mind that many devices out there are not 100% accurate, it goes for thermometer and hygrometer.

What I have in my egg box is 2 degrees off as far as temps and 15 to 20% off as far as humidity, however I know that my humidity is as high as it will go and for the temps I have double checked with my temp gun.

I still use the device as a guideline knowing my temps are higher than shown same for humidity.

I also use substrate-less incubation, however I do not use glad press and seal.

As Ed said
As long as the eggs are staying plump and aren't getting wet. You're spot on.