Sorry, at time I was writing, and not finished, there was an outage !!
Hello there @bambi851, I am following your issue since a while, and I did actually check myself the issue you have and you have totally right, when I connect the EAF to ASIAIR APP and then go to EAF settings in ASIAIR and then click on AUTOFOCUS and there under STEP SIZE the maximum allowed step size is limited to 10-200 ( for me it is more than OK )
And if you want to have the step size to 300 then, Then you should ACTUALLY address your matter to ZWO SUPPORT TEAM directly and explain them the problem so THEY can give you support by making them aware of your issue..
@ZWO_User "#p1459 and @bambi851 has an issue with the maximum step size, can you please support?
Good luck @bambi851
Martin