As Rixington says, the quickshifter is meant to operate with the throttle open & also, as Tomfum says, at reasonable revs.
On my 800, unless I'm pulling away quickly, I use the clutch from 1st to 2nd, after that it's fine so long as you're rolling the throttle on.
Changing down, (is it bi-directional on the 1050?) yes, roll off the throttle before you change down.
Tomfum, interesting what you say about being a 'bit harsh' changing down. Mine seems the same, although I find it better if I leave a touch of throttle on & wait 'till the bike slows a bit. If I'm using the gear box to slow down I use the clutch.
I did take mine back to ask the question & the man said the chain adjustment was a bit out. I'll give it another few hundred miles & take it back to get it adjusted & see how it goes then.