Hi Kim,

I don't think that you need a new soil test. I wouldn't change the recommendations because you want to put in flowers. 

However, if you want to put in something like native plants, you might not have to use any fertilizer. Many of our native plants are adapted to "lean" soils. You can use the UM Herbarium website https://www.michiganflora.net/ to find plants native to the county and read descriptions of their native habitat. It might help you find native plants suited to your soil type. Plants like New England asters and Canada goldenrod and common milkweed would probably be very happy in your garden with no soil amendments. 

However, if you want to plant something like dahlias or roses, fertilizer will definitely be on order. For plants that are "heavy feeders", you will want to follow the recommendations on the soil test.