Varying rotation speed with spinTo

[mape2k]

Hello,

I am using the spinTo command in a for loop to spin to different view angles during an experiment. I want the rotation speed to be constant, independent from the actual and desired view angle.
However, the spinTo command gives me different rotation speeds when I use it. Sometimes its faster, and sometimes its slower, even though I specify a constant speed angle.

I have attached a working minimum example. Here, the speed will vary, seemingly at random.

import viztask
import viz
import vizact

angles = [-120,150,100,150,-170,50,90,150]

viz.addChild('piazza.osgb')
view=viz.MainView

def run():
	
	for k in angles:
		print str(k)
		yield viztask.waitKeyDown(' ')
		yield viztask.addAction(view, vizact.spinTo(euler=[k,0,0],speed=80,interpolate = vizact.linear))

viztask.schedule(run())
viz.go()

Thank you for your help in advance!