MinCapaUsage KF not working with TS Supply Optimizer

Experts:

I am trying to use the MinCapaUsage KF to force downtime on my resource for a few weeks. I've used the Violation Cost Rate for this KF & also made sure it is higher than the storage/production/transport costs. However, the TS Optimizer doesn't respect it & plans the full quantity. Our CAPASUPPLY KF is non editable as we interface it from S/4.

Any clues?

Cheers