Hello Claro, spacings are a bit tricky because they are only ever a guide. The ones I recommend have worked well for me over a long period and 45×10 gives plenty of bean stems. The only time I might thin is if they are autumn sown and every one survived the winter. Normally a few die and the others tiller with new stems to fill gaps. Wider spacing is a bit easier to pick pods.
As well as weather, it depends on soil fertility, how many stems grow from each seed. See what happens and adjust next year if necessary.
