Correct
@noblehead! Well, sorry, there ARE up and down arrows, but to add 30% you go up to 130%, to decrease by 30% you go down to 70%. I view it as de/increasing TO a percentage, rather than BY a percentage.
Basically there's an up arrow and a down arrow on the pump, and you just go either higher than the 100%, or lower.
I've just snapped a sequence to show you.
Pic 1 - normal display showing 0.65u/hr.
Pic 2 - the default on the screen when setting a TBR is 100%. Use the up or down arrows to change rate.
Pic 3 - I want to reduce it to 90%, so I've hit the down arrow.
Pic 4 - as you can see, the rate is now 90% of the full whack, ie normal basal rate MINUS 10%. You can see that, because the 0.65u has reduced to 0.59u.
And I've just realised that it would have been more helpful to illustrate this with the 30% scenario we were talking about earlier! Oooops!