I don't think it would necessarily be a bad idea to implement the heavier bell that way.
The old weights really get a lot easier to lift after getting new heavier lifts. That's why I always tell people to do heavy singles, here and at the gym, that even if they're not chasing PRs, their regular training will feel so much easier after having a taste of the heavier weight.
And it doesn't have to always be that much heavier, especially relatively taken some really small increments will do. The kettlebell is a bit lacking in that way, as the jumps are typically so large.