NavList:

Matus Tejiscak you asked if baclash makes any difference bearing in mind how you take your shots.

Yes it will.  Some shots you might bring the Sun to the bubble from above, sometimes from below (In an aeroplane you might be chasing the bubble all the time, push-pull, push-pull with your thumb,  Whoops, where's it gone now?  Oh there it is; should I push or wait for it to drift back?  But that's by the by). So, very roughly, if for shot one you brought the Sun up from below, and for shot two you brought the Sun down from above, and difference between shots would include lost motion due to backlash.