lusty rover
With one Speed-Boost Extension, the transformer wagon has a duration of "0.5 - 0.1s". Before using the second Speed-Boost extension, the preview states that the wagon will have a duration of "0.4 - 0.1s" afterwards, but with the extension used, it goes back to "0.5 - 0.1s".
Just noticed, that the first screenshot was still in German^^´
For the sake of completeness, here it is again in English
patent quarry
Most likely just a rounding error since it’s 15% speed reduction
lusty rover
Yes, might be. That's why I added both the gameplay and visual tag. I wasn't sure if this is effecting the behavior of the wagon and it is, like you said, just an error in the visuals or if the wagon is actually not benefiting from the second Speed-Boost extension.
native pollen
Indeed it's an rounding issue in the UI and I agree that it seems confusing. In the next update, when applying a extension changing value in sub 0.1 regime, we'll show an additional digit:
However when applied I'd keep the old rounding as having 2 after comma digits looks too distracting