This was my code to test, that is why the delays are 12 seconds. (should have explained that...) Actually the Intervals will be much longer: between one to three minutes.
I tested it already and it works fine. The load is only around 10 -20 grams and in my tests the precision was working well in different speed settings.
So I guess I should work without the delay() using millis() instead and creating booleans to check if the different parts of loop are true and should be executed??