I'm going to give you some unsolicated adice right now. If you have not checked that thermometer for accuracey, do it before you trust it. My first hatch I bought that exact thermometer/hygrometer. (Springfield) I never checked it. I thought my bator was running 99-100 the whole incubation. At lockdown my chicks looked a little behind, but I was new and hoping I was just wrong. At day 24 I finally had one hatch, another at day 25, but he didn't make it. I was told to check the thermometer. I did and found that it was SIX degrees off!!
As for humidity, I wouldn't go 55%, I use 30-35% and don't like seeing anything over 45%. But most importantly,checked your air cells and you'll know.