Thanks Carl!

Yes, rounding up the weight and trying to do the number of reps proposed by app, is what I'm doing right now. At least that hasn't lead to an early deload yet.

Hmm, but the increments of my dumbbell system are not constant. E.g. the dumbbells have steps like 11.5, 12.5, 13.5, 16, 17, 18, 20.5, 21.5, 22.5, 25 etc.
Even without the 1kg inlay weights, the increments are not constant (4.5, 7, 9, 11, 13.5, 18, 22.5, 27, 32).

How do I solve this with only one custom increment value?

(see my other idea for more details regarding the Powerblock https://muscle.userecho.com/communities/1/topics/140-detailed-weight-increments)