Lots of people do it all different ways, lots of ways to skin this cat.
Personally over time ive found it easier to infuse and decarb in one step, watching it carefully at roughly 280f. Takes me 30 mins about. 45 mins if im doing lower temp.
With flower, i like to do a lower temp for longer to be sure i infuse it well.
I noticed this works better for concentrates, but does work well for bud also. I think decarbing bud then infusing for longer may get you a slighly more potent batch than doing it all in one step, but i find it easier and get satisfactory results.