My experience with 901 attys is some aren't as "good" as others draw wise. Maybe the air hole placement between inner/outer collar is off.
With my 801's, vendor differences seem to be part of the key. My Janty atty is a bit harder to draw on than the generic ones I've gotten.
I guess I'd suggest getting another 1 or 2 spare attys and see how they perform. They do eventually fail so you'll get the use out of them.