Yeah, you read that 5 degrees a week on here a lot but I ignore it. If you manage the 5 degrees a week thing you will be extremely safe as far as keeping them warm enough.
Where are you located so we can have an idea about your weather and temperatures? If you modify your profile that information is always available, like mine and Debbie's. That information comes in handy for a lot of questions.
I go about it differently. I use a heat lamp in my brooder in the coop to keep one area warm enough all of the time. Since it is outside, temperature swings can cause issues with maintaining a steady temperature. I can go from below freezing to the 70's Fahrenheit in a day. So my brooder is big enough and has sufficient ventilation that one end stays toasty in the coldest weather but the far end stays cool enough in the warmest conditions. Even if the warm end is too warm the chicks simply go to where they are comfortable.
When a broody hen raises them they spend a lot of time out running around, eating, drinking, and playing. When they get cold they go back under her to warm up. I use the same principle. Many people would be surprised to see how much time the chicks spend in the cooler portions of the brooder or in cold conditions with a broody.
If you are indoors with climate controlled AC or heat, this can be a lot easier. You don't have big temperature swings so providing a place warm enough with another spot cool enough should be pretty easy.
What should I do if I'm unable to turn it down?
You are under a very common misconception. The chicks can handle cooler temperatures as they grow older but are in danger if it gets too cool too fast. Very true. That does not mean they can't handle warmer temperatures. A broody hen cannot cool off the entire farm for her chicks if the weather stays warm. Lots of broody hens raise chicks with daytime highs in the 90's Fahrenheit. They need some shade to take the chicks too if they get in really high temperatures but the chicks can handle temperatures much warmer than those you get by dropping the temperature 5 degrees a week.
I you are not able to turn it down it is not a problem as long as they aren't so hot they cook and they have a cool pace to go to.
Another misconception is that the chart for 5 degrees a week goes on forever. It doesn't. By 5 weeks of age most chicks are fully feathered and can handle much cooler temperatures than that chart shows. There is nothing wrong with providing then a place to go warm up if they want to, but give them a place they can cool off if they want to. Many people find that by 4 to 5 weeks they quit using the heat you provide.
Good luck and welcome to the adventure.