You don’t need to bolus the exact number of the preset. Presets can still be adjusted. You just use it as a starting point for dialing up or down.
You can have 7 presets. Suppose you have them preset at:
0.5
1.0
2.0
5.0
7.0
8.5
10.0
Whatever number you want to give, one of the presets is closest to it, and means you don’t need to start scrolling from 0.0
Suppose dinner and correction is 7.2 units. Would you rather scroll there from 0.0, or scroll there from 7.0?