Does the accelstepper library round the steps up? Or how does it floating steps?
Not sure, I think it takes the steps per second that you enter, takes the reciprocal (1 / x) and multiplies that by 1 million to get the step interval in microSeconds. 1 / 3.71402 * 1000000 = 269250 microSeconds or 1 step every 0.269250 seconds. Keep in mind, Arduino uses float (32 bit) NOT double for FP math, so 6 significant digits (like 3.71402 or 37140.2) is all you get.