When you write something like "stage:deltav:current", you get "Unable to find suffix deltav on type none" because it thinks "stage" refers to the "STAGE." function (which returns none) instead of the STAGE structure (defined here: https://ksp-kos.github.io/KOS/structures/vessels/stage.html)
When you write something like "stage:deltav:current", you get "Unable to find suffix deltav on type none" because it thinks "stage" refers to the "STAGE." function (which returns none) instead of the STAGE structure (defined here: https://ksp-kos.github.io/KOS/structures/vessels/stage.html)